diff --git a/bin/setup b/bin/setup
index 4b9345e..5b41ee5 100755
--- a/bin/setup
+++ b/bin/setup
@@ -7,7 +7,7 @@ bundle install
 
 set +u
 if [ -z "$BUNDLE_GEMFILE" ]; then
-  bundle exec rbs collection install
+  bundle exec rbs collection install --frozen
 else
   echo "Skipping rbs collection install because BUNDLE_GEMFILE is set"
 fi