diff --git a/src/gax-internal/tests/grpc_rust_timeout.rs b/src/gax-internal/tests/grpc_rust_timeout.rs
new file mode 100644
index 0000000000..07070acfc0
--- /dev/null
+++ b/src/gax-internal/tests/grpc_rust_timeout.rs
@@ -0,0 +1,140 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#[cfg(all(
+    test,
+    feature = "_internal-grpc-client",
+    google_cloud_unstable_grpc_rust
+))]
+mod tests {
+    use google_cloud_auth::credentials::{Credentials, anonymous::Builder as Anonymous};
+    use google_cloud_gax::options::RequestOptions;
+    use google_cloud_gax_internal::grpc::GrpcRustClient;
+    use google_cloud_gax_internal::options::ClientConfig;
+    use grpc_server::{google, start_echo_server};
+    use pretty_assertions::assert_eq;
+    use std::time::Duration;
+
+    #[tokio::test]
+    async fn no_timeout() -> anyhow::Result<()> {
+        // Arrange
+        let (endpoint, _server) = start_echo_server().await?;
+        let client = GrpcRustClient::new(test_config(), &endpoint).await?;
+
+        let delay = Duration::from_millis(50);
+        let request_options = RequestOptions::default();
+
+        // Act
+        let response = send_request(client, request_options, "great success!", Some(delay)).await?;
+
+        // Assert
+        assert_eq!(response.message, "great success!");
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn timeout_does_not_expire() -> anyhow::Result<()> {
+        // Arrange
+        let (endpoint, _server) = start_echo_server().await?;
+        let client = GrpcRustClient::new(test_config(), &endpoint).await?;
+
+        let delay = Duration::from_millis(50);
+        let timeout = Duration::from_millis(2000);
+        let mut request_options = RequestOptions::default();
+        request_options.set_attempt_timeout(timeout);
+
+        // Act
+        let response = send_request(client, request_options, "great success!", Some(delay)).await?;
+
+        // Assert
+        assert_eq!(response.message, "great success!");
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn timeout_expires() -> anyhow::Result<()> {
+        // Arrange
+        let (endpoint, _server) = start_echo_server().await?;
+        let client = GrpcRustClient::new(test_config(), &endpoint).await?;
+
+        let delay = Duration::from_millis(500);
+        let timeout = Duration::from_millis(50);
+        let mut request_options = RequestOptions::default();
+        request_options.set_attempt_timeout(timeout);
+
+        // Act
+        let response = send_request(client, request_options, "should timeout", Some(delay)).await;
+
+        // Assert
+        let err = response.expect_err("should timeout");
+        assert!(err.is_timeout(), "{err:?}");
+        Ok(())
+    }
+
+    #[tokio::test]
+    async fn client_config_timeout() -> anyhow::Result<()> {
+        // Arrange
+        let (endpoint, _server) = start_echo_server().await?;
+
+        let mut config = test_config();
+        config.attempt_timeout = Some(Duration::from_millis(50));
+
+        let client = GrpcRustClient::new(config, &endpoint).await?;
+
+        let delay = Duration::from_millis(500);
+        let request_options = RequestOptions::default();
+
+        // Act
+        let response = send_request(client, request_options, "should timeout", Some(delay)).await;
+
+        // Assert
+        let err = response.expect_err("should timeout");
+        assert!(err.is_timeout(), "{err:?}");
+        Ok(())
+    }
+
+    fn test_credentials() -> Credentials {
+        Anonymous::new().build()
+    }
+
+    fn test_config() -> ClientConfig {
+        let mut config = ClientConfig::default();
+        config.cred = Some(test_credentials());
+        config
+    }
+
+    async fn send_request(
+        client: GrpcRustClient,
+        options: RequestOptions,
+        msg: &str,
+        delay: Option<Duration>,
+    ) -> google_cloud_gax::Result<google::test::v1::EchoResponse> {
+        let delay_ms = delay.map(|d| d.as_millis() as u64);
+        let request = google::test::v1::EchoRequest {
+            message: msg.into(),
+            delay_ms,
+        };
+        client
+            .execute(
+                tonic::Extensions::new(),
+                http::uri::PathAndQuery::from_static("/google.test.v1.EchoService/Echo"),
+                request,
+                options,
+                "test-only-api-client/1.0",
+                "",
+            )
+            .await
+            .map(tonic::Response::into_inner)
+    }
+}