diff --git a/pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart b/pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart
index 7ba8e46d7bb..8d10082606a 100644
--- a/pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart
+++ b/pkg/analyzer/lib/src/error/unused_local_elements_verifier.dart
@@ -70,6 +70,13 @@ class GatherUsedLocalElementsVisitor extends RecursiveAstVisitor<void> {
 
   @override
   void visitClassDeclaration(ClassDeclaration node) {
+    var element = node.declaredElement;
+    if (element != null) {
+      if (element.hasJS) {
+        usedElements.addElement(element);
+      }
+    }
+
     var enclosingClassOld = _enclosingClass;
     try {
       _enclosingClass = node.declaredElement;
diff --git a/pkg/analyzer/test/src/diagnostics/unused_element_test.dart b/pkg/analyzer/test/src/diagnostics/unused_element_test.dart
index a8b21638bd5..64b40b96af2 100644
--- a/pkg/analyzer/test/src/diagnostics/unused_element_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/unused_element_test.dart
@@ -84,6 +84,28 @@ void f(Object p) {
 ''');
   }
 
+  test_class_isUsed_jsAnnotation() async {
+    writeTestPackageConfig(
+      PackageConfigFileBuilder()
+        ..add(name: 'js', rootPath: '$workspaceRootPath/js'),
+    );
+
+    newFile('$workspaceRootPath/js/lib/js.dart', r'''
+library _js_annotations;
+
+class JS {
+  const JS();
+}
+''');
+
+    await assertNoErrorsInCode(r'''
+import 'package:js/js.dart';
+
+@JS()
+class _A {}
+''');
+  }
+
   test_class_notUsed_isExpression_typeArgument() async {
     await assertErrorsInCode(r'''
 class _A {}