diff --git a/tutorial/dart/Makefile.am b/tutorial/dart/Makefile.am
index ccca598..438e457 100644
--- a/tutorial/dart/Makefile.am
+++ b/tutorial/dart/Makefile.am
@@ -30,6 +30,7 @@
 	$(RM) -r gen-*
 	find . -type d -name "packages" | xargs $(RM) -r
 	find . -type f -name ".packages" | xargs $(RM)
+	find . -type f -name "pubspec.lock" | xargs $(RM)
 
 pub-get: pub-get-gen pub-get-client pub-get-console-client pub-get-server