diff --git a/Sources/_FoundationCShims/CMakeLists.txt b/Sources/_FoundationCShims/CMakeLists.txt
index 1798a5bb0..5bf8e9a11 100644
--- a/Sources/_FoundationCShims/CMakeLists.txt
+++ b/Sources/_FoundationCShims/CMakeLists.txt
@@ -19,8 +19,10 @@ add_library(_FoundationCShims STATIC
 
 target_include_directories(_FoundationCShims PUBLIC include)
 
-target_compile_options(_FoundationCShims INTERFACE
-  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=${CMAKE_CURRENT_SOURCE_DIR}/include/module.modulemap>")
+if(NOT CMAKE_SYSTEM_NAME STREQUAL "Windows")
+  target_compile_options(_FoundationCShims INTERFACE
+    "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-Xcc -fmodule-map-file=${CMAKE_CURRENT_SOURCE_DIR}/include/module.modulemap>")
+endif()
 
 set_property(GLOBAL APPEND PROPERTY SWIFT_FOUNDATION_EXPORTS _FoundationCShims)