diff --git a/packages/angular_devkit/build_angular/src/webpack/plugins/karma-debug.html b/packages/angular_devkit/build_angular/src/webpack/plugins/karma-debug.html
index 8c3fe313059d..44dbff5898f4 100644
--- a/packages/angular_devkit/build_angular/src/webpack/plugins/karma-debug.html
+++ b/packages/angular_devkit/build_angular/src/webpack/plugins/karma-debug.html
@@ -9,6 +9,7 @@
 <head>
 %X_UA_COMPATIBLE%
   <title>Karma DEBUG RUNNER</title>
+  <base href="/">
   <link href="favicon.ico" rel="icon" type="image/x-icon" />
   <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
   <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no" />
