diff --git a/tools/gn b/tools/gn
index 421a4862b875aeadeda59e7a0f4d38de0f4be0b7..1e96bf8aacfebe390772c40e739e7275034a7f90 100755
--- a/tools/gn
+++ b/tools/gn
@@ -119,6 +119,9 @@ def to_gn_args(args):
     else:
         gn_args['dart_runtime_mode'] = runtime_mode
 
+    if args.dart_debug:
+        gn_args['dart_debug'] = True
+
     if args.target_os == 'android':
         gn_args['target_cpu'] = args.android_cpu
     elif args.target_os == 'ios':
@@ -209,6 +212,7 @@ def parse_args(args):
   parser.add_argument('--runtime-mode', type=str, choices=['debug', 'profile', 'release'], default='debug')
   parser.add_argument('--dynamic', default=False, action='store_true')
   parser.add_argument('--interpreter', default=False, action='store_true')
+  parser.add_argument('--dart-debug', default=False, action='store_true')
 
   parser.add_argument('--target-os', type=str, choices=['android', 'ios', 'linux'])
   parser.add_argument('--android', dest='target_os', action='store_const', const='android')