diff --git a/engine/src/flutter/tools/run_third_party_dart.py b/engine/src/flutter/tools/run_third_party_dart.py
index 74f30c5f75..9fef936ec0 100644
--- a/engine/src/flutter/tools/run_third_party_dart.py
+++ b/engine/src/flutter/tools/run_third_party_dart.py
@@ -3,8 +3,13 @@
 # found in the LICENSE file.
 
 import subprocess
+import os
 
 if __name__ == '__main__':
-    subprocess.call(["src/third_party/dart/tools/sdks/dart-sdk/bin/pub", "global", "activate", "-spath", "./src/flutter/tools/generate_package_config"])
-    subprocess.call(["src/third_party/dart/tools/sdks/dart-sdk/bin/pub", "global", "run", "generate_package_config:generate_from_legacy", "src/flutter/flutter_frontend_server/.packages"])
-    subprocess.call(["src/third_party/dart/tools/sdks/dart-sdk/bin/pub", "global", "run", "generate_package_config:generate_from_legacy", "src/flutter/tools/const_finder/.packages"])
+    leading = os.path.join("src", "third_party", "dart", "tools", "sdks", "dart-sdk", "bin")
+    pub = "pub"
+    if os.name == "nt":
+        pub = "pub.bat"
+    subprocess.check_call([os.path.join(leading, pub), "global", "activate", "-spath", "./src/flutter/tools/generate_package_config"])
+    subprocess.check_call([os.path.join(leading, pub), "global", "run", "generate_package_config:generate_from_legacy", "src/flutter/flutter_frontend_server/.packages"])
+    subprocess.check_call([os.path.join(leading, pub), "global", "run", "generate_package_config:generate_from_legacy", "src/flutter/tools/const_finder/.packages"])