diff --git a/packages/angular_devkit/build_angular/src/builders/karma/find-tests-plugin.ts b/packages/angular_devkit/build_angular/src/builders/karma/find-tests-plugin.ts
index 256f4506c0c4..6fc935393ed8 100644
--- a/packages/angular_devkit/build_angular/src/builders/karma/find-tests-plugin.ts
+++ b/packages/angular_devkit/build_angular/src/builders/karma/find-tests-plugin.ts
@@ -132,6 +132,7 @@ async function findMatchingTests(
     root: projectSourceRoot,
     nomount: true,
     absolute: true,
+    ignore: ['**/node_modules/**'],
   });
 }