diff --git a/.gitignore b/.gitignore
index ca019d656b..8111f6535f 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,7 @@
 .repo
 .settings
 out/*
+
+# Ignore llvm-build. This is only when you are using clang. Address Sanitizer
+# requires clang.
+/third_party/llvm-build/