diff --git a/bin/pull-all.sh b/bin/pull-all.sh
index c4b7a6914..950b8ef65 100755
--- a/bin/pull-all.sh
+++ b/bin/pull-all.sh
@@ -15,6 +15,7 @@ POLYMER_PATH=${POLYMER_PATH:-"https://github.com/Polymer"}
 REPOS=(
   CustomElements
   HTMLImports
+  MutationObservers
   NodeBind
   PointerEvents
   PointerGestures