diff --git a/llvm/utils/gn/secondary/clang/test/BUILD.gn b/llvm/utils/gn/secondary/clang/test/BUILD.gn
index ed255a668b40..85ba3cc76793 100644
--- a/llvm/utils/gn/secondary/clang/test/BUILD.gn
+++ b/llvm/utils/gn/secondary/clang/test/BUILD.gn
@@ -59,6 +59,7 @@ write_lit_config("lit_site_cfg") {
     "CMAKE_C_COMPILER=cc",
     "ENABLE_BACKTRACES=1",
     "LLVM_ENABLE_NEW_PASS_MANAGER=1",
+    "LLVM_EXTERNAL_LIT=",
     "LLVM_HOST_TRIPLE=$llvm_current_triple",
     "LLVM_LIT_TOOLS_DIR=",  # Intentionally empty, matches cmake build.
     "LLVM_USE_SANITIZER=",