diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-context.html b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-context.html
index 5de33896d7db..cef84e87c8ea 100644
--- a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-context.html
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-context.html
@@ -29,6 +29,7 @@
   </script>
   <script src="_karma_webpack_/runtime.js" crossorigin="anonymous"></script>
   <script src="_karma_webpack_/polyfills.js" crossorigin="anonymous"></script>
+  <script src="_karma_webpack_/polyfills-es5.js" crossorigin="anonymous" nomodule></script>
   <!-- Dynamically replaced with <script> tags -->
   %SCRIPTS%
   <script src="_karma_webpack_/styles.js" crossorigin="anonymous"></script>
diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html
index 93a8a2005d6f..93739d39b7cf 100644
--- a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma-debug.html
@@ -30,6 +30,7 @@
   </script>
   <script src="_karma_webpack_/runtime.js" crossorigin="anonymous"></script>
   <script src="_karma_webpack_/polyfills.js" crossorigin="anonymous"></script>
+  <script src="_karma_webpack_/polyfills-es5.js" crossorigin="anonymous" nomodule></script>
   <!-- Dynamically replaced with <script> tags -->
   %SCRIPTS%
   <script src="_karma_webpack_/styles.js" crossorigin="anonymous"></script>
diff --git a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma.ts b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma.ts
index a009ab2abab5..ca4958baf4a9 100644
--- a/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma.ts
+++ b/packages/angular_devkit/build_angular/src/angular-cli-files/plugins/karma.ts
@@ -209,6 +209,7 @@ const init: any = (config: any, emitter: any, customFileHandlers: any) => {
         const alwaysServe = [
           '/_karma_webpack_/runtime.js',
           '/_karma_webpack_/polyfills.js',
+          '/_karma_webpack_/polyfills-es5.js',
           '/_karma_webpack_/scripts.js',
           '/_karma_webpack_/styles.js',
           '/_karma_webpack_/vendor.js',