diff --git a/Cargo.lock b/Cargo.lock
index 0d5c46953f3967..81ab85e438bccc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1661,6 +1661,7 @@ dependencies = [
  "http-body-util",
  "import_map",
  "indexmap 2.9.0",
+ "json5",
  "jsonc-parser",
  "jupyter-protocol",
  "keyring",
@@ -1744,9 +1745,9 @@ dependencies = [
 
 [[package]]
 name = "deno_ast"
-version = "0.50.3"
+version = "0.51.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6c6fca2bd99b9f4ac51e548a34b74f8e397d94694a6ced184315922156f70ed0"
+checksum = "c72e0409b3dbd60a5bf296cbc273a8e36bb3a3aab6abac389f1891e187d5ce14"
 dependencies = [
  "base64 0.22.1",
  "capacity_builder",
@@ -1837,9 +1838,9 @@ dependencies = [
 
 [[package]]
 name = "deno_cache_dir"
-version = "0.25.0"
+version = "0.26.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "19ab8c76d18a8a7511825bfb93e8b35e79b3dd8404a48c570c536db2a3c88855"
+checksum = "dd048472e451169f443461ab1a6362186af32c6a8b2204de219a7834fc231a28"
 dependencies = [
  "async-trait",
  "base32",
@@ -2011,8 +2012,6 @@ dependencies = [
 [[package]]
 name = "deno_doc"
 version = "0.186.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "92de7919430e4bd66edace9ca4ca1dba7599ddf627bfa35a8c919b99ed5f54cf"
 dependencies = [
  "anyhow",
  "cfg-if",
@@ -2164,8 +2163,6 @@ dependencies = [
 [[package]]
 name = "deno_graph"
 version = "0.103.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "293db685464cf8a18785e32d6fdcfffb78a864465d8e9017bfb005ccacc560a8"
 dependencies = [
  "async-trait",
  "boxed_error",
@@ -2335,9 +2332,9 @@ dependencies = [
 
 [[package]]
 name = "deno_lint"
-version = "0.80.0"
+version = "0.81.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "816be0fe885ac88b200d73d99f8c9557278ff416acf8abc1661b46837f09a303"
+checksum = "aa4da1c0d215a8d89f28b9c8778795683c975e76255d7f00049447d6f04fe93d"
 dependencies = [
  "anyhow",
  "deno_ast",
@@ -2374,9 +2371,9 @@ dependencies = [
 
 [[package]]
 name = "deno_media_type"
-version = "0.2.9"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f0ec0dada9dc5ac4733b4175d36f6a150b7dd68fab46db35cb1ef00dd7366acb"
+checksum = "757b57d3e748bb5fc98cb010f33b0ed03f6aa3a7c70166cbdd529c1809ca3118"
 dependencies = [
  "data-url",
  "encoding_rs",
@@ -2852,6 +2849,8 @@ dependencies = [
  "hyper 1.6.0",
  "hyper-util",
  "indexmap 2.9.0",
+ "json5",
+ "jsonc-parser",
  "libc",
  "log",
  "nix 0.27.1",
@@ -2863,6 +2862,7 @@ dependencies = [
  "rustyline",
  "same-file",
  "serde",
+ "serde_json",
  "sys_traits",
  "test_server",
  "thiserror 2.0.12",
@@ -3639,9 +3639,9 @@ dependencies = [
 
 [[package]]
 name = "dprint-plugin-typescript"
-version = "0.95.11"
+version = "0.95.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "74aa5df06eb156f7df91bf17a0ca65fd349dfa22463c3eab0a019bab20df12df"
+checksum = "ed62468ffd2bc0a759497022c7e20ec08f15d74057ad17c0bfa5b3ca657e8c8d"
 dependencies = [
  "anyhow",
  "capacity_builder",
@@ -3931,8 +3931,6 @@ dependencies = [
 [[package]]
 name = "eszip"
 version = "0.104.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dde1007099ac5d0184579513aa0d5484ad25d9638a21c7c26203548aebe40d9b"
 dependencies = [
  "anyhow",
  "async-trait",
@@ -5552,6 +5550,17 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "json5"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96b0db21af676c1ce64250b5f40f3ce2cf27e4e47cb91ed91eb6fe9350b430c1"
+dependencies = [
+ "pest",
+ "pest_derive",
+ "serde",
+]
+
 [[package]]
 name = "jsonc-parser"
 version = "0.27.0"
diff --git a/Cargo.toml b/Cargo.toml
index a7a419e9ef9d9b..36b0e983415477 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -53,6 +53,11 @@ members = [
 ]
 exclude = ["tests/util/std/hash/_wasm"]
 
+[patch.crates-io]
+deno_graph = { path = "../deno_graph" }
+eszip = { path = "../eszip" }
+deno_doc = { path = "../deno_doc" }
+
 [workspace.package]
 authors = ["the Deno authors"]
 edition = "2024"
@@ -60,16 +65,16 @@ license = "MIT"
 repository = "https://github.com/denoland/deno"
 
 [workspace.dependencies]
-deno_ast = { version = "=0.50.3", features = ["transpiling"] }
+deno_ast = { version = "=0.51.0", features = ["transpiling"] }
 deno_core = { version = "0.367.0" }
 
-deno_cache_dir = "=0.25.0"
+deno_cache_dir = "=0.26.1"
 deno_doc = "=0.186.0"
 deno_error = "=0.7.0"
 deno_graph = { version = "=0.103.1", default-features = false }
-deno_lint = "=0.80.0"
+deno_lint = "=0.81.0"
 deno_lockfile = "=0.32.2"
-deno_media_type = { version = "=0.2.9", features = ["module_specifier"] }
+deno_media_type = { version = "=0.3.2", features = ["module_specifier"] }
 deno_native_certs = "0.3.0"
 deno_npm = "=0.42.0"
 deno_path_util = "=0.6.4"
@@ -196,6 +201,7 @@ indexmap = { version = "2", features = ["serde"] }
 ipnet = "2.3"
 ipnetwork = "0.20.0"
 itertools = "0.14"
+json5 = "0.4.1"
 jsonc-parser = { version = "0.27.0", features = ["serde"] }
 jupyter_runtime = "=0.19.0"
 lazy-regex = "3"
@@ -308,7 +314,7 @@ dprint-core = "=0.67.4"
 dprint-plugin-json = "=0.21.0"
 dprint-plugin-jupyter = "=0.2.1"
 dprint-plugin-markdown = "=0.20.0"
-dprint-plugin-typescript = "=0.95.11"
+dprint-plugin-typescript = "=0.95.12"
 env_logger = "=0.11.6"
 fancy-regex = "=0.14.0"
 libsui = "0.10.0"
diff --git a/cli/Cargo.toml b/cli/Cargo.toml
index 69fa23ac802e99..30b54d02b3e316 100644
--- a/cli/Cargo.toml
+++ b/cli/Cargo.toml
@@ -133,6 +133,7 @@ http-body.workspace = true
 http-body-util.workspace = true
 import_map.workspace = true
 indexmap.workspace = true
+json5.workspace = true
 jsonc-parser = { workspace = true, features = ["cst", "serde"] }
 jupyter-protocol = "0.8.0"
 jupyter_runtime = { package = "runtimelib", version = "=0.28.0", default-features = false, features = ["tokio-runtime", "aws-lc-rs"] }
diff --git a/cli/cache/module_info.rs b/cli/cache/module_info.rs
index e13c595c19cc2b..7279f8f78b3f1d 100644
--- a/cli/cache/module_info.rs
+++ b/cli/cache/module_info.rs
@@ -305,12 +305,14 @@ fn serialize_media_type(media_type: MediaType) -> i64 {
     Dcts => 10,
     Tsx => 11,
     Json => 12,
-    Wasm => 13,
-    Css => 14,
-    Html => 15,
-    SourceMap => 16,
-    Sql => 17,
-    Unknown => 18,
+    Jsonc => 13,
+    Json5 => 14,
+    Wasm => 15,
+    Css => 16,
+    Html => 17,
+    SourceMap => 18,
+    Sql => 19,
+    Unknown => 20,
   }
 }
 
diff --git a/cli/lib/loader.rs b/cli/lib/loader.rs
index bdd111ae734c56..bfc3c30a487bad 100644
--- a/cli/lib/loader.rs
+++ b/cli/lib/loader.rs
@@ -16,13 +16,12 @@ pub fn module_type_from_media_and_requested_type(
   match requested_module_type {
     RequestedModuleType::Text => ModuleType::Text,
     RequestedModuleType::Bytes => ModuleType::Bytes,
-    RequestedModuleType::None
-    | RequestedModuleType::Other(_)
-    | RequestedModuleType::Json => match media_type {
+    RequestedModuleType::None | RequestedModuleType::Json => match media_type {
       MediaType::Json => ModuleType::Json,
       MediaType::Wasm => ModuleType::Wasm,
       _ => ModuleType::JavaScript,
     },
+    RequestedModuleType::Other(t) => ModuleType::Other(t.clone()),
   }
 }
 
@@ -67,6 +66,12 @@ pub fn as_deno_resolver_requested_module_type(
     RequestedModuleType::Bytes => {
       deno_resolver::loader::RequestedModuleType::Bytes
     }
+    RequestedModuleType::Other(Cow::Borrowed("jsonc")) => {
+      deno_resolver::loader::RequestedModuleType::Jsonc
+    }
+    RequestedModuleType::Other(Cow::Borrowed("json5")) => {
+      deno_resolver::loader::RequestedModuleType::Json5
+    }
     RequestedModuleType::Other(text) => {
       deno_resolver::loader::RequestedModuleType::Other(text)
     }
diff --git a/cli/lib/standalone/binary.rs b/cli/lib/standalone/binary.rs
index 81bfed31099f32..ddbfaaeb399527 100644
--- a/cli/lib/standalone/binary.rs
+++ b/cli/lib/standalone/binary.rs
@@ -243,12 +243,14 @@ fn serialize_media_type(media_type: MediaType) -> u8 {
     MediaType::Dcts => 9,
     MediaType::Tsx => 10,
     MediaType::Json => 11,
-    MediaType::Wasm => 12,
-    MediaType::Css => 13,
-    MediaType::Html => 14,
-    MediaType::SourceMap => 15,
-    MediaType::Sql => 16,
-    MediaType::Unknown => 17,
+    MediaType::Jsonc => 12,
+    MediaType::Json5 => 13,
+    MediaType::Wasm => 14,
+    MediaType::Css => 15,
+    MediaType::Html => 16,
+    MediaType::SourceMap => 17,
+    MediaType::Sql => 18,
+    MediaType::Unknown => 19,
   }
 }
 
diff --git a/cli/lsp/config.rs b/cli/lsp/config.rs
index e832938a0fca02..ea8e8c45c237ce 100644
--- a/cli/lsp/config.rs
+++ b/cli/lsp/config.rs
@@ -1053,6 +1053,8 @@ impl Config {
       | MediaType::Dcts
       | MediaType::Tsx => Some(&workspace_settings.typescript),
       MediaType::Json
+      | MediaType::Jsonc
+      | MediaType::Json5
       | MediaType::Wasm
       | MediaType::Css
       | MediaType::Html
diff --git a/cli/lsp/diagnostics.rs b/cli/lsp/diagnostics.rs
index bafb9f1a665942..5033b42c20d053 100644
--- a/cli/lsp/diagnostics.rs
+++ b/cli/lsp/diagnostics.rs
@@ -935,7 +935,7 @@ fn diagnose_resolution(
           if module.media_type == MediaType::Json {
             match maybe_assert_type {
               // The module has the correct assertion type, no diagnostic
-              Some("json" | "text" | "bytes") => (),
+              Some("json" | "jsonc" | "json5" | "text" | "bytes") => (),
               // The dynamic import statement is missing an attribute type, which
               // we might not be able to statically detect, therefore we will
               // not provide a potentially incorrect diagnostic.
diff --git a/cli/lsp/documents.rs b/cli/lsp/documents.rs
index d662fe701915ec..b0571ddf4364f2 100644
--- a/cli/lsp/documents.rs
+++ b/cli/lsp/documents.rs
@@ -145,6 +145,10 @@ impl OpenDocument {
     self.language_id.is_diagnosable()
   }
 
+  pub fn is_diagnosable_or_typed(&self) -> bool {
+    self.language_id.is_diagnosable_or_typed()
+  }
+
   pub fn is_file_like(&self) -> bool {
     uri_is_file_like(&self.uri)
   }
@@ -1714,7 +1718,8 @@ pub enum LanguageId {
   TypeScript,
   Tsx,
   Json,
-  JsonC,
+  Jsonc,
+  Json5,
   Markdown,
   Html,
   Css,
@@ -1739,7 +1744,8 @@ impl LanguageId {
       LanguageId::TypeScript => Some("ts"),
       LanguageId::Tsx => Some("tsx"),
       LanguageId::Json => Some("json"),
-      LanguageId::JsonC => Some("jsonc"),
+      LanguageId::Jsonc => Some("jsonc"),
+      LanguageId::Json5 => Some("json5"),
       LanguageId::Markdown => Some("md"),
       LanguageId::Html => Some("html"),
       LanguageId::Css => Some("css"),
@@ -1759,14 +1765,16 @@ impl LanguageId {
 
   pub fn as_content_type(&self) -> Option<&'static str> {
     match self {
-      LanguageId::JavaScript => Some("application/javascript"),
-      LanguageId::Jsx => Some("text/jsx"),
-      LanguageId::TypeScript => Some("application/typescript"),
-      LanguageId::Tsx => Some("text/tsx"),
-      LanguageId::Json | LanguageId::JsonC => Some("application/json"),
+      LanguageId::JavaScript => MediaType::JavaScript.as_content_type(),
+      LanguageId::Jsx => MediaType::Jsx.as_content_type(),
+      LanguageId::TypeScript => MediaType::TypeScript.as_content_type(),
+      LanguageId::Tsx => MediaType::Tsx.as_content_type(),
+      LanguageId::Json => MediaType::Json.as_content_type(),
+      LanguageId::Jsonc => MediaType::Jsonc.as_content_type(),
+      LanguageId::Json5 => MediaType::Json5.as_content_type(),
       LanguageId::Markdown => Some("text/markdown"),
-      LanguageId::Html => Some("text/html"),
-      LanguageId::Css => Some("text/css"),
+      LanguageId::Html => MediaType::Html.as_content_type(),
+      LanguageId::Css => MediaType::Css.as_content_type(),
       LanguageId::Scss => None,
       LanguageId::Sass => None,
       LanguageId::Less => None,
@@ -1787,6 +1795,19 @@ impl LanguageId {
       Self::JavaScript | Self::Jsx | Self::TypeScript | Self::Tsx
     )
   }
+
+  fn is_diagnosable_or_typed(&self) -> bool {
+    matches!(
+      self,
+      Self::JavaScript
+        | Self::Jsx
+        | Self::TypeScript
+        | Self::Tsx
+        | Self::Json
+        | Self::Jsonc
+        | Self::Json5
+    )
+  }
 }
 
 impl FromStr for LanguageId {
@@ -1799,7 +1820,8 @@ impl FromStr for LanguageId {
       "typescript" => Ok(Self::TypeScript),
       "typescriptreact" | "tsx" => Ok(Self::Tsx),
       "json" => Ok(Self::Json),
-      "jsonc" => Ok(Self::JsonC),
+      "jsonc" => Ok(Self::Jsonc),
+      "json5" => Ok(Self::Json5),
       "markdown" => Ok(Self::Markdown),
       "html" => Ok(Self::Html),
       "css" => Ok(Self::Css),
diff --git a/cli/lsp/language_server.rs b/cli/lsp/language_server.rs
index 967ac96138059b..9f8b999a683627 100644
--- a/cli/lsp/language_server.rs
+++ b/cli/lsp/language_server.rs
@@ -1128,17 +1128,15 @@ impl Inner {
             | MediaType::Dmts
             | MediaType::Dcts
             | MediaType::Json
+            | MediaType::Jsonc
+            | MediaType::Json5
             | MediaType::Tsx => {}
             MediaType::Wasm
             | MediaType::SourceMap
             | MediaType::Css
             | MediaType::Html
             | MediaType::Sql
-            | MediaType::Unknown => {
-              if path.extension().and_then(|s| s.to_str()) != Some("jsonc") {
-                continue;
-              }
-            }
+            | MediaType::Unknown => continue,
           }
           dir_files.insert(path);
         }
@@ -1335,7 +1333,7 @@ impl Inner {
       params.text_document.text.into(),
       None,
     );
-    if document.is_diagnosable() {
+    if document.is_diagnosable_or_typed() {
       self.check_semantic_tokens_capabilities();
       self.refresh_dep_info();
       self.project_changed(
@@ -1380,7 +1378,7 @@ impl Inner {
       }
     }
     if let Some(document) = document
-      && document.is_diagnosable()
+      && document.is_diagnosable_or_typed()
     {
       self.refresh_dep_info();
       self.project_changed(
@@ -1504,7 +1502,7 @@ impl Inner {
         return;
       }
     };
-    if document.is_diagnosable() {
+    if document.is_diagnosable_or_typed() {
       self.refresh_dep_info();
       self.project_changed(
         vec![(Document::Open(document), ChangeKind::Closed)],
@@ -1524,7 +1522,7 @@ impl Inner {
     );
     let diagnosable_documents = documents
       .into_iter()
-      .filter(|d| d.is_diagnosable())
+      .filter(|d| d.is_diagnosable_or_typed())
       .collect::<Vec<_>>();
     if !diagnosable_documents.is_empty() {
       self.check_semantic_tokens_capabilities();
@@ -1552,7 +1550,7 @@ impl Inner {
     );
     let diagnosable_documents = documents
       .into_iter()
-      .filter(|(d, _)| d.is_diagnosable())
+      .filter(|(d, _)| d.is_diagnosable_or_typed())
       .collect::<Vec<_>>();
     if !diagnosable_documents.is_empty() {
       self.refresh_dep_info();
@@ -1601,7 +1599,7 @@ impl Inner {
       .close_notebook_document(&params.notebook_document.uri);
     let diagnosable_documents = documents
       .into_iter()
-      .filter(|d| d.is_diagnosable())
+      .filter(|d| d.is_diagnosable_or_typed())
       .collect::<Vec<_>>();
     if !diagnosable_documents.is_empty() {
       self.refresh_dep_info();
diff --git a/cli/lsp/tsc.rs b/cli/lsp/tsc.rs
index a32291637698c3..2455fbb620c5d2 100644
--- a/cli/lsp/tsc.rs
+++ b/cli/lsp/tsc.rs
@@ -4620,7 +4620,8 @@ impl TscSpecifierMap {
     }
     // If the module's media type doesn't correspond to tsc's path-inferred
     // media type, force it to be the same by appending an extension.
-    if MediaType::from_path(Path::new(&specifier)) != media_type {
+    let ts_extension = media_type.as_ts_extension();
+    if !specifier.as_str().ends_with(ts_extension) {
       specifier += media_type.as_ts_extension();
     }
     if specifier != original.as_str() {
diff --git a/cli/module_loader.rs b/cli/module_loader.rs
index 8a586e33816ebc..ebfcfecd6e7aa9 100644
--- a/cli/module_loader.rs
+++ b/cli/module_loader.rs
@@ -1236,7 +1236,7 @@ impl<TGraphContainer: ModuleGraphContainer> ModuleLoader
     let graph = self.0.graph_container.graph();
     let code = match graph.get(&resolve_url(file_name).ok()?) {
       Some(deno_graph::Module::Js(module)) => &module.source.text,
-      Some(deno_graph::Module::Json(module)) => &module.source.text,
+      Some(deno_graph::Module::Independent(module)) => &module.source.text,
       _ => return None,
     };
     // Do NOT use .lines(): it skips the terminating empty line.
diff --git a/cli/rt/binary.rs b/cli/rt/binary.rs
index aee8fd160a028c..0471b969b38d7c 100644
--- a/cli/rt/binary.rs
+++ b/cli/rt/binary.rs
@@ -446,6 +446,14 @@ impl<'a> DenoCompileModuleData<'a> {
         ModuleType::Json,
         into_string_unsafe(self.is_valid_utf8, data),
       ),
+      MediaType::Jsonc => (
+        ModuleType::Other(Cow::Borrowed("jsonc")),
+        into_string_unsafe(self.is_valid_utf8, data),
+      ),
+      MediaType::Json5 => (
+        ModuleType::Other(Cow::Borrowed("json5")),
+        into_string_unsafe(self.is_valid_utf8, data),
+      ),
       MediaType::Wasm => {
         (ModuleType::Wasm, DenoCompileModuleSource::Bytes(data))
       }
diff --git a/cli/standalone/binary.rs b/cli/standalone/binary.rs
index 842ba89c75a11b..89fcfa01f98fa2 100644
--- a/cli/standalone/binary.rs
+++ b/cli/standalone/binary.rs
@@ -481,7 +481,7 @@ impl<'a> DenoCompileBinaryWriter<'a> {
           }
           (Some(original_bytes), m.media_type)
         }
-        deno_graph::Module::Json(m) => {
+        deno_graph::Module::Independent(m) => {
           let original_bytes = match m.source.try_get_original_bytes() {
             Some(bytes) => bytes,
             None => {
diff --git a/cli/tools/bundle/mod.rs b/cli/tools/bundle/mod.rs
index c2bbd2d04bbd9b..78f9f16dcd29c9 100644
--- a/cli/tools/bundle/mod.rs
+++ b/cli/tools/bundle/mod.rs
@@ -776,6 +776,8 @@ fn requested_type_from_map(
   let type_ = map.get("type").map(|s| s.as_str());
   match type_ {
     Some("json") => RequestedModuleType::Json,
+    Some("jsonc") => RequestedModuleType::Jsonc,
+    Some("json5") => RequestedModuleType::Json5,
     Some("bytes") => RequestedModuleType::Bytes,
     Some("text") => RequestedModuleType::Text,
     Some(other) => RequestedModuleType::Other(other),
@@ -1109,6 +1111,12 @@ pub enum BundleLoadError {
   #[error("Emit error")]
   Emit(#[from] deno_ast::EmitError),
   #[class(generic)]
+  #[error("{}", if let Self::Jsonc(Some(err)) = &self { Cow::Owned(format!("Couldn't parse jsonc file: {err}")) } else { Cow::Borrowed("Empty jsonc file") })]
+  Jsonc(#[from] Option<jsonc_parser::errors::ParseError>),
+  #[class(generic)]
+  #[error("{}", if let Self::Json5(err) = &self { format!("Couldn't parse json5 file: {err}") } else { unreachable!() })]
+  Json5(#[from] json5::Error),
+  #[class(generic)]
   #[error("Prepare module load error")]
   PrepareModuleLoad(#[from] crate::module_loader::PrepareModuleLoadError),
 
@@ -1396,6 +1404,8 @@ impl DenoPluginHandler {
             }
             RequestedModuleType::None
             | RequestedModuleType::Json
+            | RequestedModuleType::Jsonc
+            | RequestedModuleType::Json5
             | RequestedModuleType::Other(_) => {
               if media_type.is_emittable() {
                 let str = String::from_utf8_lossy(&file.source);
@@ -1476,6 +1486,25 @@ impl DenoPluginHandler {
       Some(RequestedModuleType::Json) => {
         return Ok((source.to_vec(), esbuild_client::BuiltinLoader::Json));
       }
+      Some(RequestedModuleType::Jsonc) => {
+        let jsonc_str = String::from_utf8_lossy(source);
+        let json_str =
+          jsonc_parser::parse_to_serde_value(&jsonc_str, &Default::default())
+            .map_err(|err| BundleLoadError::Jsonc(Some(err)))?
+            .ok_or_else(|| BundleLoadError::Jsonc(None))?
+            .to_string();
+        return Ok((
+          json_str.into_bytes(),
+          esbuild_client::BuiltinLoader::Json,
+        ));
+      }
+      Some(RequestedModuleType::Json5) => {
+        let json5_str = String::from_utf8_lossy(source);
+        json5::from_str::<serde_json::Value>(&json5_str)
+          .map_err(BundleLoadError::Json5)?;
+        let js_str = format!("export default ({json5_str});");
+        return Ok((js_str.into_bytes(), esbuild_client::BuiltinLoader::Js));
+      }
       Some(RequestedModuleType::Other(_) | RequestedModuleType::None)
       | None => {}
     }
@@ -1599,7 +1628,7 @@ impl DenoPluginHandler {
         js_module.media_type,
         media_type_to_loader(js_module.media_type),
       ),
-      deno_graph::Module::Json(json_module) => (
+      deno_graph::Module::Independent(json_module) => (
         json_module.specifier.clone(),
         deno_ast::MediaType::Json,
         esbuild_client::BuiltinLoader::Json,
@@ -1662,6 +1691,8 @@ fn media_type_to_loader(
     Sql => esbuild_client::BuiltinLoader::Text,
     Wasm => esbuild_client::BuiltinLoader::Binary,
     Unknown => esbuild_client::BuiltinLoader::Binary,
+    // TODO(This PR): Investigate.
+    Jsonc | Json5 => esbuild_client::BuiltinLoader::Json,
     // _ => esbuild_client::BuiltinLoader::External,
   }
 }
diff --git a/cli/tools/clean.rs b/cli/tools/clean.rs
index 94ad05b0fb3eb7..c8929765698afe 100644
--- a/cli/tools/clean.rs
+++ b/cli/tools/clean.rs
@@ -240,7 +240,7 @@ async fn clean_except(
         deno_graph::Module::Js(js_module) => {
           keep.insert(&js_module.specifier);
         }
-        deno_graph::Module::Json(json_module) => {
+        deno_graph::Module::Independent(json_module) => {
           keep.insert(&json_module.specifier);
         }
         deno_graph::Module::Wasm(wasm_module) => {
diff --git a/cli/tools/compile.rs b/cli/tools/compile.rs
index 79ae3a003fbc74..94e2098adfbe9c 100644
--- a/cli/tools/compile.rs
+++ b/cli/tools/compile.rs
@@ -366,6 +366,8 @@ fn get_module_roots_and_include_paths(
       | MediaType::Dcts
       | MediaType::Tsx
       | MediaType::Json
+      | MediaType::Jsonc
+      | MediaType::Json5
       | MediaType::Wasm => true,
       MediaType::Css
       | MediaType::Html
diff --git a/cli/tools/coverage/mod.rs b/cli/tools/coverage/mod.rs
index d88c9bd69fd554..73f884c0c01af3 100644
--- a/cli/tools/coverage/mod.rs
+++ b/cli/tools/coverage/mod.rs
@@ -555,6 +555,8 @@ pub fn cover_files(
       | MediaType::Wasm
       | MediaType::Cjs
       | MediaType::Mjs
+      | MediaType::Jsonc
+      | MediaType::Json5
       | MediaType::Json => None,
       MediaType::Dts | MediaType::Dmts | MediaType::Dcts => Some(String::new()),
       MediaType::TypeScript
diff --git a/cli/tools/info.rs b/cli/tools/info.rs
index 6ee6624c73d85a..15653416f6888d 100644
--- a/cli/tools/info.rs
+++ b/cli/tools/info.rs
@@ -503,7 +503,7 @@ impl<'a> GraphDisplayContext<'a> {
       Ok(Some(root)) => {
         let maybe_cache_info = match root {
           Module::Js(module) => module.maybe_cache_info.as_ref(),
-          Module::Json(module) => module.maybe_cache_info.as_ref(),
+          Module::Independent(module) => module.maybe_cache_info.as_ref(),
           Module::Wasm(module) => module.maybe_cache_info.as_ref(),
           Module::Node(_) | Module::Npm(_) | Module::External(_) => None,
         };
@@ -526,7 +526,7 @@ impl<'a> GraphDisplayContext<'a> {
           .map(|m| {
             let size = match m {
               Module::Js(module) => module.size(),
-              Module::Json(module) => module.size(),
+              Module::Independent(module) => module.size(),
               Module::Wasm(module) => module.size(),
               Module::Node(_) | Module::Npm(_) | Module::External(_) => 0,
             };
@@ -635,7 +635,7 @@ impl<'a> GraphDisplayContext<'a> {
         }
         Specifier(_) => match module {
           Module::Js(module) => Some(module.size() as u64),
-          Module::Json(module) => Some(module.size() as u64),
+          Module::Independent(module) => Some(module.size() as u64),
           Module::Wasm(module) => Some(module.size() as u64),
           Module::Node(_) | Module::Npm(_) | Module::External(_) => None,
         },
@@ -667,7 +667,7 @@ impl<'a> GraphDisplayContext<'a> {
               tree_node.children.extend(self.build_dep_info(dep));
             }
           }
-          Module::Json(_)
+          Module::Independent(_)
           | Module::Npm(_)
           | Module::Node(_)
           | Module::External(_) => {}
diff --git a/cli/tools/publish/mod.rs b/cli/tools/publish/mod.rs
index 529756a3945d4b..8e5ed03cfe7b5a 100644
--- a/cli/tools/publish/mod.rs
+++ b/cli/tools/publish/mod.rs
@@ -1094,7 +1094,7 @@ fn collect_excluded_module_diagnostics(
     .modules()
     .filter_map(|m| match m {
       deno_graph::Module::Js(_)
-      | deno_graph::Module::Json(_)
+      | deno_graph::Module::Independent(_)
       | deno_graph::Module::Wasm(_) => Some(m.specifier()),
       deno_graph::Module::Npm(_)
       | deno_graph::Module::Node(_)
diff --git a/cli/tools/publish/module_content.rs b/cli/tools/publish/module_content.rs
index 5355cf9ec68e8f..73d997065f5531 100644
--- a/cli/tools/publish/module_content.rs
+++ b/cli/tools/publish/module_content.rs
@@ -92,6 +92,8 @@ impl<TSys: FsMetadata + FsRead> ModuleContentProvider<TSys> {
           | MediaType::Html
           | MediaType::Sql
           | MediaType::Json
+          | MediaType::Jsonc
+          | MediaType::Json5
           | MediaType::Wasm
           | MediaType::Css => {
             // not unfurlable data
diff --git a/cli/tsc/mod.rs b/cli/tsc/mod.rs
index 2ab2a44641889b..aad927c7bd2df2 100644
--- a/cli/tsc/mod.rs
+++ b/cli/tsc/mod.rs
@@ -513,6 +513,8 @@ pub fn as_ts_script_kind(media_type: MediaType) -> i32 {
     MediaType::Dcts => 3,
     MediaType::Tsx => 4,
     MediaType::Json => 6,
+    MediaType::Jsonc => 6,
+    MediaType::Json5 => 6,
     MediaType::SourceMap
     | MediaType::Css
     | MediaType::Html
@@ -657,8 +659,14 @@ fn resolve_graph_specifier_types(
     Some(Module::Js(module)) => {
       Ok(Some((module.specifier.clone(), module.media_type)))
     }
-    Some(Module::Json(module)) => {
-      Ok(Some((module.specifier.clone(), module.media_type)))
+    Some(Module::Independent(module)) => {
+      let media_type = match module.media_type {
+        MediaType::Json | MediaType::Jsonc | MediaType::Json5 => {
+          MediaType::Json
+        }
+        _ => module.media_type,
+      };
+      Ok(Some((module.specifier.clone(), media_type)))
     }
     Some(Module::Wasm(module)) => {
       Ok(Some((module.specifier.clone(), MediaType::Dmts)))
@@ -951,7 +959,7 @@ pub fn resolve_specifier_for_tsc(
   let resolved_dep = referrer_module
     .and_then(|m| match m {
       Module::Js(m) => m.dependencies_prefer_fast_check().get(&specifier),
-      Module::Json(_) => None,
+      Module::Independent(_) => None,
       Module::Wasm(m) => m.dependencies.get(&specifier),
       Module::Npm(_) | Module::Node(_) | Module::External(_) => None,
     })
@@ -1144,9 +1152,18 @@ pub fn load_for_tsc<T: LoadContent, M: Mapper>(
               .unwrap_or(T::from_arc_str(module.source.text.clone())),
           )
         }
-        Module::Json(module) => {
-          media_type = MediaType::Json;
-          Some(T::from_arc_str(module.source.text.clone()))
+        Module::Independent(module) => {
+          match module.media_type {
+            MediaType::Jsonc | MediaType::Json5 => {
+              media_type = MediaType::Json;
+              Some(T::from_arc_str(module.source.text.clone()))
+            }
+            // Expecting `MediaType::Json`.
+            _ => {
+              media_type = module.media_type;
+              Some(T::from_arc_str(module.source.text.clone()))
+            }
+          }
         }
         Module::Wasm(module) => {
           media_type = MediaType::Dts;
diff --git a/cli/type_checker.rs b/cli/type_checker.rs
index 81906d803417ef..b784842c2454f6 100644
--- a/cli/type_checker.rs
+++ b/cli/type_checker.rs
@@ -783,7 +783,7 @@ impl<'a> GraphWalker<'a> {
         Module::Wasm(module) => {
           maybe_module_dependencies = Some(&module.dependencies);
         }
-        Module::Json(_) | Module::Npm(_) => {}
+        Module::Independent(_) | Module::Npm(_) => {}
         Module::External(module) => {
           // NPM files for `"nodeModulesDir": "manual"`.
           let media_type = MediaType::from_specifier(&module.specifier);
@@ -881,6 +881,8 @@ impl<'a> GraphWalker<'a> {
             }
           }
           MediaType::Json
+          | MediaType::Jsonc
+          | MediaType::Json5
           | MediaType::Wasm
           | MediaType::Css
           | MediaType::Html
@@ -913,7 +915,7 @@ impl<'a> GraphWalker<'a> {
         // which is hashed below
         None
       }
-      Module::Json(module) => {
+      Module::Independent(module) => {
         if let Some(hasher) = &mut self.maybe_hasher {
           hasher.write_str(module.specifier.as_str());
           hasher.write_str(&module.source.text);
@@ -997,6 +999,8 @@ fn has_ts_check(media_type: MediaType, file_text: &str) -> bool {
     | MediaType::Dmts
     | MediaType::Tsx
     | MediaType::Json
+    | MediaType::Jsonc
+    | MediaType::Json5
     | MediaType::Wasm
     | MediaType::Css
     | MediaType::Html
diff --git a/libs/resolver/cjs/mod.rs b/libs/resolver/cjs/mod.rs
index aa6198957a3c5f..07676513513b03 100644
--- a/libs/resolver/cjs/mod.rs
+++ b/libs/resolver/cjs/mod.rs
@@ -199,7 +199,7 @@ impl<TInNpmPackageChecker: InNpmPackageChecker, TSys: FsRead + FsMetadata>
         self.check_based_on_pkg_json(specifier).unwrap_or(ResolutionMode::Import)
       }
       MediaType::Wasm |
-      MediaType::Json => ResolutionMode::Import,
+      MediaType::Json | MediaType::Jsonc | MediaType::Json5 => ResolutionMode::Import,
       MediaType::JavaScript
       | MediaType::Jsx
       | MediaType::TypeScript
@@ -246,7 +246,7 @@ impl<TInNpmPackageChecker: InNpmPackageChecker, TSys: FsRead + FsMetadata>
         }
       }
       MediaType::Wasm |
-      MediaType::Json => Some(ResolutionMode::Import),
+      MediaType::Json | MediaType::Jsonc | MediaType::Json5 => Some(ResolutionMode::Import),
       MediaType::JavaScript
       | MediaType::Jsx
       | MediaType::TypeScript
diff --git a/libs/resolver/emit.rs b/libs/resolver/emit.rs
index 320dbdb5f1bf4a..66e4e2896e1f71 100644
--- a/libs/resolver/emit.rs
+++ b/libs/resolver/emit.rs
@@ -357,6 +357,8 @@ impl<TInNpmPackageChecker: InNpmPackageChecker, TSys: EmitterSys>
       | MediaType::Dmts
       | MediaType::Dcts
       | MediaType::Json
+      | MediaType::Jsonc
+      | MediaType::Json5
       | MediaType::Wasm
       | MediaType::Css
       | MediaType::Html
diff --git a/libs/resolver/graph.rs b/libs/resolver/graph.rs
index abe9eb04c46142..0c77f24e52b8eb 100644
--- a/libs/resolver/graph.rs
+++ b/libs/resolver/graph.rs
@@ -304,7 +304,7 @@ impl<
       }
       Some(Module::Node(module)) => module.specifier.clone(),
       Some(Module::Js(module)) => module.specifier.clone(),
-      Some(Module::Json(module)) => module.specifier.clone(),
+      Some(Module::Independent(module)) => module.specifier.clone(),
       Some(Module::Wasm(module)) => module.specifier.clone(),
       Some(Module::External(module)) => {
         node_resolver::resolve_specifier_into_node_modules(
diff --git a/libs/resolver/loader/mod.rs b/libs/resolver/loader/mod.rs
index 3689245cd00723..d181796a0a0761 100644
--- a/libs/resolver/loader/mod.rs
+++ b/libs/resolver/loader/mod.rs
@@ -27,6 +27,8 @@ pub enum AllowJsonImports {
 pub enum RequestedModuleType<'a> {
   None,
   Json,
+  Jsonc,
+  Json5,
   Text,
   Bytes,
   Other(&'a str),
diff --git a/libs/resolver/loader/module_loader.rs b/libs/resolver/loader/module_loader.rs
index d34e69a8c652c7..7d729a64643d51 100644
--- a/libs/resolver/loader/module_loader.rs
+++ b/libs/resolver/loader/module_loader.rs
@@ -4,8 +4,8 @@ use std::borrow::Cow;
 
 use boxed_error::Boxed;
 use deno_ast::ModuleKind;
+use deno_graph::IndependentModule;
 use deno_graph::JsModule;
-use deno_graph::JsonModule;
 use deno_graph::ModuleGraph;
 use deno_graph::WasmModule;
 use deno_media_type::MediaType;
@@ -409,7 +409,7 @@ impl<TSys: ModuleLoaderSys> PreparedModuleLoader<TSys> {
       })?;
 
     match maybe_module {
-      Some(deno_graph::Module::Json(JsonModule {
+      Some(deno_graph::Module::Independent(IndependentModule {
         source,
         media_type,
         specifier,
@@ -474,7 +474,9 @@ impl<TSys: ModuleLoaderSys> PreparedModuleLoader<TSys> {
             MediaType::JavaScript
             | MediaType::Unknown
             | MediaType::Mjs
-            | MediaType::Json => source.text.clone(),
+            | MediaType::Json
+            | MediaType::Jsonc
+            | MediaType::Json5 => source.text.clone(),
             MediaType::Dts | MediaType::Dcts | MediaType::Dmts => {
               Default::default()
             }
diff --git a/libs/resolver/loader/npm.rs b/libs/resolver/loader/npm.rs
index 765499050dff26..95df3d5c8d8b45 100644
--- a/libs/resolver/loader/npm.rs
+++ b/libs/resolver/loader/npm.rs
@@ -196,6 +196,8 @@ impl<
       }
       RequestedModuleType::None
       | RequestedModuleType::Json
+      | RequestedModuleType::Jsonc
+      | RequestedModuleType::Json5
       | RequestedModuleType::Other(_) => {
         if media_type.is_emittable() {
           return Err(NpmModuleLoadError::StrippingTypesNodeModules(
diff --git a/libs/resolver/workspace.rs b/libs/resolver/workspace.rs
index fb09342fb0f2e0..a6f9016c2d08ab 100644
--- a/libs/resolver/workspace.rs
+++ b/libs/resolver/workspace.rs
@@ -543,6 +543,8 @@ impl<TSys: FsMetadata> SloppyImportsResolver<TSys> {
             | MediaType::Dcts
             | MediaType::Tsx
             | MediaType::Json
+            | MediaType::Jsonc
+            | MediaType::Json5
             | MediaType::Wasm
             | MediaType::Css
             | MediaType::Html
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index 4862a585142130..605a4e812b3f69 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -81,6 +81,8 @@ http-body-util.workspace = true
 hyper.workspace = true
 hyper-util.workspace = true
 indexmap.workspace = true
+json5.workspace = true
+jsonc-parser.workspace = true
 libc.workspace = true
 log.workspace = true
 notify.workspace = true
@@ -89,6 +91,7 @@ regex.workspace = true
 rustyline = { workspace = true, features = ["custom-bindings"] }
 same-file.workspace = true
 serde.workspace = true
+serde_json.workspace = true
 sys_traits.workspace = true
 thiserror.workspace = true
 tokio.workspace = true
diff --git a/runtime/web_worker.rs b/runtime/web_worker.rs
index 2284cabacfae7b..1737feb937da26 100644
--- a/runtime/web_worker.rs
+++ b/runtime/web_worker.rs
@@ -72,6 +72,7 @@ use crate::worker::FormatJsErrorFn;
 use crate::worker::MEMORY_TRIM_HANDLER_ENABLED;
 #[cfg(target_os = "linux")]
 use crate::worker::SIGUSR2_RX;
+use crate::worker::create_custom_module_evaluation_cb;
 use crate::worker::create_op_metrics;
 use crate::worker::create_validate_import_attributes_callback;
 
@@ -659,7 +660,7 @@ impl WebWorker {
       v8_platform: None,
       is_main: false,
       wait_for_inspector_disconnect_callback: None,
-      custom_module_evaluation_cb: None,
+      custom_module_evaluation_cb: Some(create_custom_module_evaluation_cb()),
       eval_context_code_cache_cbs: None,
     });
 
diff --git a/runtime/worker.rs b/runtime/worker.rs
index c477cc615c4a3c..939fd1fb8be1da 100644
--- a/runtime/worker.rs
+++ b/runtime/worker.rs
@@ -103,7 +103,7 @@ pub fn create_validate_import_attributes_callback(
       let valid_attribute = |kind: &str| {
         enable_raw_imports.load(Ordering::Relaxed)
           && matches!(kind, "bytes" | "text")
-          || matches!(kind, "json")
+          || matches!(kind, "json" | "jsonc" | "json5")
       };
       for (key, value) in attributes {
         let msg = if key != "type" {
@@ -129,6 +129,107 @@ pub fn create_validate_import_attributes_callback(
   )
 }
 
+pub const BOM_CHAR: &[u8] = &[0xef, 0xbb, 0xbf];
+
+/// Strips the byte order mark from the provided text if it exists.
+fn strip_bom(source_code: &[u8]) -> &[u8] {
+  if source_code.starts_with(BOM_CHAR) {
+    &source_code[BOM_CHAR.len()..]
+  } else {
+    source_code
+  }
+}
+
+// TODO(nayeemrmn): Export this from deno_core.
+type CustomModuleEvaluationCb = Box<
+  dyn Fn(
+    &mut v8::PinScope,
+    Cow<'_, str>,
+    &deno_core::FastString,
+    deno_core::ModuleSourceCode,
+  ) -> Result<
+    deno_core::CustomModuleEvaluationKind,
+    deno_error::JsErrorBox,
+  >,
+>;
+
+pub fn create_custom_module_evaluation_cb() -> CustomModuleEvaluationCb {
+  Box::new(
+    |scope, module_type, module_name, code| match module_type.as_ref() {
+      "jsonc" => {
+        let json_str = jsonc_parser::parse_to_serde_value(
+          deno_core::ModuleSource::get_string_source(code).as_str(),
+          &Default::default(),
+        )
+        .map_err(|err| {
+          deno_error::JsErrorBox::type_error(format!(
+            "Couldn't parse jsonc file \"{module_name}\": {err}"
+          ))
+        })?
+        .ok_or_else(|| {
+          deno_error::JsErrorBox::type_error(format!(
+            "Empty jsonc file: {module_name}"
+          ))
+        })?
+        .to_string();
+        let json_str = v8::String::new_from_utf8(
+          scope,
+          strip_bom(json_str.as_bytes()),
+          v8::NewStringType::Normal,
+        )
+        .unwrap();
+        v8::tc_scope!(let tc_scope, scope);
+        let parsed_json = v8::json::parse(tc_scope, json_str).ok_or_else(|| {
+          assert!(tc_scope.has_caught());
+          deno_error::JsErrorBox::type_error(format!(
+            "Internal error: A jsonc file was successfully converted to json, but the output could not be parsed by v8: {module_name}",
+          ))
+        })?;
+        let parsed_json = v8::Global::new(tc_scope, parsed_json);
+        Ok(deno_core::CustomModuleEvaluationKind::Synthetic(
+          parsed_json,
+        ))
+      }
+      "json5" => {
+        let json5_str = deno_core::ModuleSource::get_string_source(code);
+        json5::from_str::<serde_json::Value>(json5_str.as_str()).map_err(
+          |err| {
+            deno_error::JsErrorBox::type_error(format!(
+              "Couldn't parse json5 file \"{module_name}\": {err}"
+            ))
+          },
+        )?;
+        let expr_str = format!("({json5_str})");
+        let expr_str = v8::String::new_from_utf8(
+          scope,
+          strip_bom(expr_str.as_bytes()),
+          v8::NewStringType::Normal,
+        )
+        .unwrap();
+        v8::tc_scope!(let tc_scope, scope);
+        let script =
+          v8::Script::compile(tc_scope, expr_str, None).ok_or_else(|| {
+            assert!(tc_scope.has_caught());
+            deno_error::JsErrorBox::type_error(format!(
+              "Internal error: A json5 file was validated, but the output could not be parsed by v8: {module_name}",
+            ))
+          })?;
+        let result = script.run(tc_scope).ok_or_else(|| {
+          assert!(tc_scope.has_caught());
+          deno_error::JsErrorBox::type_error(format!(
+            "Internal error: A json5 file was validated, but the output could not be evaluated by v8: {module_name}",
+          ))
+        })?;
+        let result = v8::Global::new(tc_scope, result);
+        Ok(deno_core::CustomModuleEvaluationKind::Synthetic(result))
+      }
+      module_type => Err(deno_error::JsErrorBox::type_error(format!(
+        "\"{module_type}\" is not a valid module type."
+      ))),
+    },
+  )
+}
+
 pub fn make_wait_for_inspector_disconnect_callback() -> Box<dyn Fn()> {
   let has_notified_of_inspector_disconnect = AtomicBool::new(false);
   Box::new(move || {
@@ -1147,7 +1248,7 @@ fn common_runtime(opts: CommonRuntimeOptions) -> JsRuntime {
       .then(create_permissions_stack_trace_callback),
     extension_code_cache: None,
     v8_platform: None,
-    custom_module_evaluation_cb: None,
+    custom_module_evaluation_cb: Some(create_custom_module_evaluation_cb()),
     eval_context_code_cache_cbs: None,
   });
 
diff --git a/tests/specs/bundle/json5/__test__.jsonc b/tests/specs/bundle/json5/__test__.jsonc
new file mode 100644
index 00000000000000..5ae383d51c1dd3
--- /dev/null
+++ b/tests/specs/bundle/json5/__test__.jsonc
@@ -0,0 +1,10 @@
+{
+  "tempDir": true,
+  "steps": [{
+    "args": "bundle -o=./out.js main.ts",
+    "output": "[WILDCARD]"
+  }, {
+    "args": "run ./out.js",
+    "output": "main.out"
+  }]
+}
diff --git a/tests/specs/bundle/json5/foo.json5 b/tests/specs/bundle/json5/foo.json5
new file mode 100644
index 00000000000000..d086805884988e
--- /dev/null
+++ b/tests/specs/bundle/json5/foo.json5
@@ -0,0 +1,14 @@
+// Adapted from https://json5.org/.
+{
+  // comments
+  unquoted: 'and you can quote me on that',
+  singleQuotes: 'I can use "double quotes" here',
+  lineBreaks: "Look, Mom! \
+No \\n's!",
+  hexadecimal: 0xdecaf,
+  leadingDecimalPoint: .8675309, andTrailing: 8675309.,
+  positiveSign: +1,
+  trailingComma: 'in objects', andIn: ['arrays',],
+  "backwardsCompatible": "with JSON",
+  specialNumbers: [NaN, Infinity, -Infinity],
+}
diff --git a/tests/specs/bundle/json5/main.out b/tests/specs/bundle/json5/main.out
new file mode 100644
index 00000000000000..9e55c9dd4fa6d5
--- /dev/null
+++ b/tests/specs/bundle/json5/main.out
@@ -0,0 +1,13 @@
+{
+  unquoted: "and you can quote me on that",
+  singleQuotes: 'I can use "double quotes" here',
+  lineBreaks: "Look, Mom! No \\n's!",
+  hexadecimal: 912559,
+  leadingDecimalPoint: 0.8675309,
+  andTrailing: 8675309,
+  positiveSign: 1,
+  trailingComma: "in objects",
+  andIn: [ "arrays" ],
+  backwardsCompatible: "with JSON",
+  specialNumbers: [ NaN, Infinity, -Infinity ]
+}
diff --git a/tests/specs/bundle/json5/main.ts b/tests/specs/bundle/json5/main.ts
new file mode 100644
index 00000000000000..75f33de8946f85
--- /dev/null
+++ b/tests/specs/bundle/json5/main.ts
@@ -0,0 +1,2 @@
+import foo from "./foo.json5" with { type: "json5" };
+console.log(foo);
diff --git a/tests/specs/bundle/jsonc/__test__.jsonc b/tests/specs/bundle/jsonc/__test__.jsonc
new file mode 100644
index 00000000000000..5ae383d51c1dd3
--- /dev/null
+++ b/tests/specs/bundle/jsonc/__test__.jsonc
@@ -0,0 +1,10 @@
+{
+  "tempDir": true,
+  "steps": [{
+    "args": "bundle -o=./out.js main.ts",
+    "output": "[WILDCARD]"
+  }, {
+    "args": "run ./out.js",
+    "output": "main.out"
+  }]
+}
diff --git a/tests/specs/bundle/jsonc/foo.jsonc b/tests/specs/bundle/jsonc/foo.jsonc
new file mode 100644
index 00000000000000..dcb53d9312636f
--- /dev/null
+++ b/tests/specs/bundle/jsonc/foo.jsonc
@@ -0,0 +1,4 @@
+{
+  // comments
+  "key": "value",
+}
diff --git a/tests/specs/bundle/jsonc/main.out b/tests/specs/bundle/jsonc/main.out
new file mode 100644
index 00000000000000..709a292905d057
--- /dev/null
+++ b/tests/specs/bundle/jsonc/main.out
@@ -0,0 +1 @@
+{ key: "value" }
diff --git a/tests/specs/bundle/jsonc/main.ts b/tests/specs/bundle/jsonc/main.ts
new file mode 100644
index 00000000000000..e047d6e02bd605
--- /dev/null
+++ b/tests/specs/bundle/jsonc/main.ts
@@ -0,0 +1,2 @@
+import foo from "./foo.jsonc" with { type: "jsonc" };
+console.log(foo);
diff --git a/tests/specs/check/json5/__test__.jsonc b/tests/specs/check/json5/__test__.jsonc
new file mode 100644
index 00000000000000..546b3fb770e759
--- /dev/null
+++ b/tests/specs/check/json5/__test__.jsonc
@@ -0,0 +1,5 @@
+{
+  "args": "check --quiet main.ts",
+  "output": "main.out",
+  "exitCode": 1
+}
diff --git a/tests/specs/check/json5/foo.json5 b/tests/specs/check/json5/foo.json5
new file mode 100644
index 00000000000000..465e55a2cf369a
--- /dev/null
+++ b/tests/specs/check/json5/foo.json5
@@ -0,0 +1,3 @@
+{
+  value: NaN,
+}
diff --git a/tests/specs/check/json5/main.out b/tests/specs/check/json5/main.out
new file mode 100644
index 00000000000000..124657f96664db
--- /dev/null
+++ b/tests/specs/check/json5/main.out
@@ -0,0 +1,6 @@
+TS2322 [ERROR]: Type 'number' is not assignable to type 'string'.
+const _value: string = foo.value;
+      ~~~~~~
+    at [WILDLINE]/main.ts:3:7
+
+error: Type checking failed.
diff --git a/tests/specs/check/json5/main.ts b/tests/specs/check/json5/main.ts
new file mode 100644
index 00000000000000..09146867fd0637
--- /dev/null
+++ b/tests/specs/check/json5/main.ts
@@ -0,0 +1,3 @@
+import foo from "./foo.json5" with { type: "json5" };
+
+const _value: string = foo.value;
diff --git a/tests/specs/check/jsonc/__test__.jsonc b/tests/specs/check/jsonc/__test__.jsonc
new file mode 100644
index 00000000000000..546b3fb770e759
--- /dev/null
+++ b/tests/specs/check/jsonc/__test__.jsonc
@@ -0,0 +1,5 @@
+{
+  "args": "check --quiet main.ts",
+  "output": "main.out",
+  "exitCode": 1
+}
diff --git a/tests/specs/check/jsonc/foo.jsonc b/tests/specs/check/jsonc/foo.jsonc
new file mode 100644
index 00000000000000..faf42feb61c86d
--- /dev/null
+++ b/tests/specs/check/jsonc/foo.jsonc
@@ -0,0 +1,4 @@
+{
+  // comments
+  "value": 1,
+}
diff --git a/tests/specs/check/jsonc/main.out b/tests/specs/check/jsonc/main.out
new file mode 100644
index 00000000000000..124657f96664db
--- /dev/null
+++ b/tests/specs/check/jsonc/main.out
@@ -0,0 +1,6 @@
+TS2322 [ERROR]: Type 'number' is not assignable to type 'string'.
+const _value: string = foo.value;
+      ~~~~~~
+    at [WILDLINE]/main.ts:3:7
+
+error: Type checking failed.
diff --git a/tests/specs/check/jsonc/main.ts b/tests/specs/check/jsonc/main.ts
new file mode 100644
index 00000000000000..e3eb8d915212c2
--- /dev/null
+++ b/tests/specs/check/jsonc/main.ts
@@ -0,0 +1,3 @@
+import foo from "./foo.jsonc" with { type: "jsonc" };
+
+const _value: string = foo.value;
diff --git a/tests/specs/run/json5/__test__.jsonc b/tests/specs/run/json5/__test__.jsonc
new file mode 100644
index 00000000000000..7444877103b8ed
--- /dev/null
+++ b/tests/specs/run/json5/__test__.jsonc
@@ -0,0 +1,4 @@
+{
+  "args": "run --quiet main.ts",
+  "output": "main.out"
+}
diff --git a/tests/specs/run/json5/foo.json5 b/tests/specs/run/json5/foo.json5
new file mode 100644
index 00000000000000..d086805884988e
--- /dev/null
+++ b/tests/specs/run/json5/foo.json5
@@ -0,0 +1,14 @@
+// Adapted from https://json5.org/.
+{
+  // comments
+  unquoted: 'and you can quote me on that',
+  singleQuotes: 'I can use "double quotes" here',
+  lineBreaks: "Look, Mom! \
+No \\n's!",
+  hexadecimal: 0xdecaf,
+  leadingDecimalPoint: .8675309, andTrailing: 8675309.,
+  positiveSign: +1,
+  trailingComma: 'in objects', andIn: ['arrays',],
+  "backwardsCompatible": "with JSON",
+  specialNumbers: [NaN, Infinity, -Infinity],
+}
diff --git a/tests/specs/run/json5/main.out b/tests/specs/run/json5/main.out
new file mode 100644
index 00000000000000..9e55c9dd4fa6d5
--- /dev/null
+++ b/tests/specs/run/json5/main.out
@@ -0,0 +1,13 @@
+{
+  unquoted: "and you can quote me on that",
+  singleQuotes: 'I can use "double quotes" here',
+  lineBreaks: "Look, Mom! No \\n's!",
+  hexadecimal: 912559,
+  leadingDecimalPoint: 0.8675309,
+  andTrailing: 8675309,
+  positiveSign: 1,
+  trailingComma: "in objects",
+  andIn: [ "arrays" ],
+  backwardsCompatible: "with JSON",
+  specialNumbers: [ NaN, Infinity, -Infinity ]
+}
diff --git a/tests/specs/run/json5/main.ts b/tests/specs/run/json5/main.ts
new file mode 100644
index 00000000000000..75f33de8946f85
--- /dev/null
+++ b/tests/specs/run/json5/main.ts
@@ -0,0 +1,2 @@
+import foo from "./foo.json5" with { type: "json5" };
+console.log(foo);
diff --git a/tests/specs/run/jsonc/__test__.jsonc b/tests/specs/run/jsonc/__test__.jsonc
new file mode 100644
index 00000000000000..7444877103b8ed
--- /dev/null
+++ b/tests/specs/run/jsonc/__test__.jsonc
@@ -0,0 +1,4 @@
+{
+  "args": "run --quiet main.ts",
+  "output": "main.out"
+}
diff --git a/tests/specs/run/jsonc/foo.jsonc b/tests/specs/run/jsonc/foo.jsonc
new file mode 100644
index 00000000000000..dcb53d9312636f
--- /dev/null
+++ b/tests/specs/run/jsonc/foo.jsonc
@@ -0,0 +1,4 @@
+{
+  // comments
+  "key": "value",
+}
diff --git a/tests/specs/run/jsonc/main.out b/tests/specs/run/jsonc/main.out
new file mode 100644
index 00000000000000..709a292905d057
--- /dev/null
+++ b/tests/specs/run/jsonc/main.out
@@ -0,0 +1 @@
+{ key: "value" }
diff --git a/tests/specs/run/jsonc/main.ts b/tests/specs/run/jsonc/main.ts
new file mode 100644
index 00000000000000..e047d6e02bd605
--- /dev/null
+++ b/tests/specs/run/jsonc/main.ts
@@ -0,0 +1,2 @@
+import foo from "./foo.jsonc" with { type: "jsonc" };
+console.log(foo);