diff --git a/tools/dockerfile/grpc_clang_format/clang_format_all_the_things.sh b/tools/dockerfile/grpc_clang_format/clang_format_all_the_things.sh
index 830d018304c87d6d1df18e0616bcfc4be0d015c6..6f4155944c3bc609f7fc1ceaf8c40c406f441f3f 100755
--- a/tools/dockerfile/grpc_clang_format/clang_format_all_the_things.sh
+++ b/tools/dockerfile/grpc_clang_format/clang_format_all_the_things.sh
@@ -31,7 +31,7 @@
 set -e
 
 # directories to run against
-DIRS="src/core src/cpp test/core test/cpp include"
+DIRS="src/core/lib src/core/ext src/cpp test/core test/cpp include"
 
 # file matching patterns to check
 GLOB="*.h *.c *.cc"