diff --git a/packages/angular_devkit/build_angular/src/protractor/index.ts b/packages/angular_devkit/build_angular/src/protractor/index.ts
index 3899946c4ab8..2ae7bda8bec7 100644
--- a/packages/angular_devkit/build_angular/src/protractor/index.ts
+++ b/packages/angular_devkit/build_angular/src/protractor/index.ts
@@ -139,6 +139,12 @@ async function execute(
     }
   }
 
+  // Like the baseUrl in protractor config file when using the API we need to add
+  // a trailing slash when provide to the baseUrl.
+  if (baseUrl && !baseUrl.endsWith('/')) {
+    baseUrl += '/';
+  }
+
   try {
     return await runProtractor(context.workspaceRoot, { ...options, baseUrl });
   } catch {