diff --git a/.bazelignore b/.bazelignore
index dc5c301299..35656cd2d7 100644
--- a/.bazelignore
+++ b/.bazelignore
@@ -1,4 +1,6 @@
 # These are fetched as external repositories.
 third_party/abseil-cpp
 third_party/googletest
+# upb is its own Bazel repository for now.
+upb/
 _build/