diff --git a/packages/angular/build/src/builders/dev-server/tests/behavior/component-updates_spec.ts b/packages/angular/build/src/builders/dev-server/tests/behavior/component-updates_spec.ts
index d471d487c5..742e07ea3b 100644
--- a/packages/angular/build/src/builders/dev-server/tests/behavior/component-updates_spec.ts
+++ b/packages/angular/build/src/builders/dev-server/tests/behavior/component-updates_spec.ts
@@ -47,5 +47,39 @@ describeServeBuilder(executeDevServer, DEV_SERVER_BUILDER_INFO, (harness, setupT
       expect(response?.headers.get('Cache-Control')).toEqual('no-cache');
       expect(output).toBe('');
     });
+
+    it('sets ngHmrMode define to true when HMR is enabled', async () => {
+      harness.useTarget('serve', {
+        ...BASE_OPTIONS,
+        hmr: true,
+      });
+
+      await harness.writeFile(
+        'src/main.ts',
+        'declare const ngHmrMode: boolean; console.log(`HMR=${ngHmrMode}`);',
+      );
+
+      const { result, content } = await executeOnceAndFetch(harness, 'main.js');
+
+      expect(result?.success).toBeTrue();
+      expect(content).toContain('HMR=${true}');
+    });
+
+    it('sets ngHmrMode define to false when HMR is disabled', async () => {
+      harness.useTarget('serve', {
+        ...BASE_OPTIONS,
+        hmr: false,
+      });
+
+      await harness.writeFile(
+        'src/main.ts',
+        'declare const ngHmrMode: boolean; console.log(`HMR=${ngHmrMode}`);',
+      );
+
+      const { result, content } = await executeOnceAndFetch(harness, 'main.js');
+
+      expect(result?.success).toBeTrue();
+      expect(content).toContain('HMR=${false}');
+    });
   });
 });
diff --git a/packages/angular/build/src/tools/esbuild/application-code-bundle.ts b/packages/angular/build/src/tools/esbuild/application-code-bundle.ts
index 58bdd78c2d..df7371e3a4 100644
--- a/packages/angular/build/src/tools/esbuild/application-code-bundle.ts
+++ b/packages/angular/build/src/tools/esbuild/application-code-bundle.ts
@@ -600,6 +600,7 @@ function getEsBuildCommonOptions(options: NormalizedApplicationBuildOptions): Bu
       ...(optimizationOptions.scripts ? { 'ngDevMode': 'false' } : undefined),
       'ngJitMode': jit ? 'true' : 'false',
       'ngServerMode': 'false',
+      'ngHmrMode': options.templateUpdates ? 'true' : 'false',
     },
     loader: loaderExtensions,
     footer,