diff --git a/xarray/backends/file_manager.py b/xarray/backends/file_manager.py
index f7cd4675729..8f36d720de4 100644
--- a/xarray/backends/file_manager.py
+++ b/xarray/backends/file_manager.py
@@ -238,8 +238,9 @@ def close(self, needs_lock: bool = True) -> None:
         with self._optional_lock(needs_lock):
             default = None
             file = self._cache.pop(self._key, default)
-            if file is not None:
-                file.close()
+            if file is None:
+                return
+            file.close()
 
     def __del__(self) -> None:
         # If we're the only CachingFileManger referencing a unclosed file,
@@ -355,6 +356,7 @@ def __init__(
         opener: Callable[..., T_File],
         *args: Any,
         mode: Any = _OMIT_MODE,
+        lock: Lock | None | Literal[False] = None,
         kwargs: Mapping[str, Any] | None = None,
     ):
         kwargs = {} if kwargs is None else dict(kwargs)
@@ -362,6 +364,7 @@ def __init__(
         self._args = args
         self._mode = "a" if mode == "w" else mode
         self._kwargs = kwargs
+        self._lock = lock
 
         # Note: No need for locking with PickleableFileManager, because all
         # opening of files happens in the constructor.
@@ -391,10 +394,13 @@ def acquire_context(self, needs_lock: bool = True) -> Iterator[T_File]:
         yield self._get_unclosed_file()
 
     def close(self, needs_lock: bool = True) -> None:
-        del needs_lock  # unused
         if not self._closed:
             file = self._get_unclosed_file()
-            file.close()
+            if needs_lock and self._lock:
+                with self._lock:
+                    file.close()
+            else:
+                file.close()
             self._file = None
             # Remove all references to opener arguments, so they can be garbage
             # collected.
@@ -417,11 +423,11 @@ def __del__(self) -> None:
     def __getstate__(self):
         # file is intentionally omitted: we want to open it again
         opener = _get_none if self._closed else self._opener
-        return (opener, self._args, self._mode, self._kwargs)
+        return (opener, self._args, self._mode, self._lock, self._kwargs)
 
     def __setstate__(self, state) -> None:
-        opener, args, mode, kwargs = state
-        self.__init__(opener, *args, mode=mode, kwargs=kwargs)  # type: ignore[misc]
+        opener, args, mode, lock, kwargs = state
+        self.__init__(opener, *args, mode=mode, lock=lock, kwargs=kwargs)  # type: ignore[misc]
 
     def __repr__(self) -> str:
         if self._closed:
@@ -448,9 +454,16 @@ def _remove_del_methods():
 class DummyFileManager(FileManager[T_File]):
     """FileManager that simply wraps an open file in the FileManager interface."""
 
-    def __init__(self, value: T_File, *, close: Callable[[], None] | None = None):
+    def __init__(
+        self,
+        value: T_File,
+        *,
+        close: Callable[[], None] | None = None,
+        lock: Lock | None | Literal[False] = None,
+    ):
         if close is None:
             close = value.close
+        self._lock = lock
         self._value = value
         self._close = close
 
@@ -464,5 +477,8 @@ def acquire_context(self, needs_lock: bool = True) -> Iterator[T_File]:
         yield self._value
 
     def close(self, needs_lock: bool = True) -> None:
-        del needs_lock  # unused
-        self._close()
+        if needs_lock and self._lock:
+            with self._lock:
+                self._close()
+        else:
+            self._close()
diff --git a/xarray/backends/netCDF4_.py b/xarray/backends/netCDF4_.py
index bb511f9befc..39dedd139c0 100644
--- a/xarray/backends/netCDF4_.py
+++ b/xarray/backends/netCDF4_.py
@@ -421,7 +421,7 @@ def __init__(
                         "argument is provided"
                     )
                 root = manager
-            manager = DummyFileManager(root)
+            manager = DummyFileManager(root, lock=NETCDF4_PYTHON_LOCK)
 
         self._manager = manager
         self._group = group
@@ -510,17 +510,21 @@ def open(
                 "<xarray-in-memory-write>", mode=mode, memory=memory, **kwargs
             )
             close = _CloseWithCopy(filename, nc4_dataset)
-            manager = DummyFileManager(nc4_dataset, close=close)
+            manager = DummyFileManager(nc4_dataset, close=close, lock=lock)
 
         elif isinstance(filename, bytes | memoryview):
             assert mode == "r"
             kwargs["memory"] = filename
             manager = PickleableFileManager(
-                netCDF4.Dataset, "<xarray-in-memory-read>", mode=mode, kwargs=kwargs
+                netCDF4.Dataset,
+                "<xarray-in-memory-read>",
+                mode=mode,
+                kwargs=kwargs,
+                lock=lock,
             )
         else:
             manager = CachingFileManager(
-                netCDF4.Dataset, filename, mode=mode, kwargs=kwargs
+                netCDF4.Dataset, filename, mode=mode, kwargs=kwargs, lock=lock
             )
         return cls(manager, group=group, mode=mode, lock=lock, autoclose=autoclose)