diff --git a/clang/cmake/caches/Apple-stage2.cmake b/clang/cmake/caches/Apple-stage2.cmake
index eb4827002011d..84f0a2c2a6410 100644
--- a/clang/cmake/caches/Apple-stage2.cmake
+++ b/clang/cmake/caches/Apple-stage2.cmake
@@ -13,7 +13,10 @@ set(CLANG_LINKS_TO_CREATE clang++ cc c++ CACHE STRING "")
 set(CMAKE_MACOSX_RPATH ON CACHE BOOL "")
 set(LLVM_ENABLE_ZLIB ON CACHE BOOL "")
 set(LLVM_ENABLE_BACKTRACES OFF CACHE BOOL "")
-set(LLVM_ENABLE_MODULES ON CACHE BOOL "")
+# BEGIN SWIFT
+# Unfortunately the Swift headers aren't properly modularized yet.
+set(LLVM_ENABLE_MODULES OFF CACHE BOOL "")
+# END SWIFT
 set(LLVM_EXTERNALIZE_DEBUGINFO ON CACHE BOOL "")
 set(CLANG_PLUGIN_SUPPORT OFF CACHE BOOL "")
 set(BUG_REPORT_URL "http://developer.apple.com/bugreporter/" CACHE STRING "")