diff --git a/packages/angular/build/src/builders/dev-server/tests/behavior/build-assets_spec.ts b/packages/angular/build/src/builders/dev-server/tests/behavior/build-assets_spec.ts
index 82ecef04c209..e5a9684b489f 100644
--- a/packages/angular/build/src/builders/dev-server/tests/behavior/build-assets_spec.ts
+++ b/packages/angular/build/src/builders/dev-server/tests/behavior/build-assets_spec.ts
@@ -39,6 +39,7 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
 
       expect(result?.success).toBeTrue();
       expect(await response?.text()).toContain(javascriptFileContent);
+      expect(response?.headers.get('ETag')).toMatch(/^W\/"[^"]+"$/);
     });
 
     it('serves a project JavaScript asset unmodified', async () => {
diff --git a/packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts b/packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts
index a1aa19361c5c..4af44ce2dd6b 100644
--- a/packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts
+++ b/packages/angular/build/src/tools/vite/middlewares/assets-middleware.ts
@@ -50,7 +50,7 @@ export function createAngularAssetsMiddleware(
       // This is a workaround to serve extensionless, CSS, JS and TS files without Vite transformations.
       if (!extension || JS_TS_REGEXP.test(extension) || CSS_PREPROCESSOR_REGEXP.test(extension)) {
         const contents = readFileSync(asset.source);
-        const etag = `W/${calculateHash(contents)}`;
+        const etag = `W/"${calculateHash(contents)}"`;
         if (checkAndHandleEtag(req, res, etag)) {
           return;
         }
@@ -238,7 +238,7 @@ export function createBuildAssetsMiddleware(
         const contents =
           outputFile.origin === 'memory' ? outputFile.contents : readHandler(outputFile.source);
 
-        const etag = `W/${calculateHash(contents)}`;
+        const etag = `W/"${calculateHash(contents)}"`;
         if (checkAndHandleEtag(req, res, etag)) {
           return;
         }