diff --git a/pkgs/test/CHANGELOG.md b/pkgs/test/CHANGELOG.md
index 8e3b42940..b347424ea 100644
--- a/pkgs/test/CHANGELOG.md
+++ b/pkgs/test/CHANGELOG.md
@@ -3,6 +3,7 @@
 * Simplify the initialization of the per-suite message channel within browser
   tests. See https://github.com/dart-lang/test/issues/2065
 * Add a timeout to browser test suite loads.
+* Fix running of browser tests that use deferred loaded libraries.
 
 ## 1.24.6
 
diff --git a/pkgs/test/pubspec.yaml b/pkgs/test/pubspec.yaml
index 872b96aea..90463532d 100644
--- a/pkgs/test/pubspec.yaml
+++ b/pkgs/test/pubspec.yaml
@@ -35,7 +35,7 @@ dependencies:
 
   # Use an exact version until the test_api and test_core package are stable.
   test_api: 0.6.1
-  test_core: 0.5.6
+  test_core: 0.5.7
 
   typed_data: ^1.3.0
   web_socket_channel: ^2.0.0
diff --git a/pkgs/test/test/runner/browser/runner_test.dart b/pkgs/test/test/runner/browser/runner_test.dart
index 322c24a7e..c55cbb884 100644
--- a/pkgs/test/test/runner/browser/runner_test.dart
+++ b/pkgs/test/test/runner/browser/runner_test.dart
@@ -921,4 +921,58 @@ void main() {
       await test.shouldExit(0);
     }, tags: 'chrome');
   });
+
+  group('deferred loading', () {
+    test('can run browser tests with deferred library imports', () async {
+      await d.file('deferred.dart', '''
+int x = 1;
+''').create();
+      await d.file('test.dart', '''
+import 'package:test/test.dart';
+
+import 'deferred.dart' deferred as d;
+
+void main() {
+  test("success", () async {
+    await d.loadLibrary();
+    expect(d.x, 1);
+  });
+}
+''').create();
+      var test = await runTest(['-p', 'chrome', 'test.dart']);
+
+      expect(test.stdout, emitsThrough(contains('+1: All tests passed!')));
+      await test.shouldExit(0);
+    }, tags: 'chrome');
+
+    test('stack trace mapping works for deferred loaded libraries', () async {
+      await d.file('deferred.dart', '''
+int get x {
+  throw 'Oh no!';
+}
+''').create();
+      await d.file('test.dart', '''
+import 'package:test/test.dart';
+
+import 'deferred.dart' deferred as d;
+
+void main() {
+  test("failure", () async {
+    await d.loadLibrary();
+    expect(d.x, 1);
+  });
+}
+''').create();
+
+      var test = await runTest(['-p', 'chrome', 'test.dart']);
+      expect(
+          test.stdout,
+          containsInOrder([
+            'Oh no!',
+            'deferred.dart',
+            'test.dart',
+          ]));
+      await test.shouldExit(1);
+    }, tags: 'chrome');
+  });
 }
diff --git a/pkgs/test_core/CHANGELOG.md b/pkgs/test_core/CHANGELOG.md
index 2a0b55ffe..dba17edd4 100644
--- a/pkgs/test_core/CHANGELOG.md
+++ b/pkgs/test_core/CHANGELOG.md
@@ -1,5 +1,8 @@
 ## 0.5.7-wip
 
+* Pass --disable-program-split to dart2js to fix tests which use deferred
+  loading.
+
 ## 0.5.6
 
 * Add support for discontinuing after the first failing test with `--fail-fast`.
diff --git a/pkgs/test_core/lib/src/runner/dart2js_compiler_pool.dart b/pkgs/test_core/lib/src/runner/dart2js_compiler_pool.dart
index c1bd159b4..a1e7fc8c4 100644
--- a/pkgs/test_core/lib/src/runner/dart2js_compiler_pool.dart
+++ b/pkgs/test_core/lib/src/runner/dart2js_compiler_pool.dart
@@ -53,6 +53,7 @@ class Dart2JsCompilerPool extends CompilerPool {
         wrapperPath,
         '--out=$path',
         '--packages=${await packageConfigUri}',
+        '--disable-program-split',
         ..._extraArgs,
         ...suiteConfig.dart2jsArgs
       ];