diff --git a/libcxx/CMakeLists.txt b/libcxx/CMakeLists.txt
index a80349a11b2a..5904c06dc51c 100644
--- a/libcxx/CMakeLists.txt
+++ b/libcxx/CMakeLists.txt
@@ -330,6 +330,8 @@ endif()
 # headers
 add_compile_flags_if_supported(-nostdinc++)
 
+# Let the library headers know they are currently being used to build the
+# library.
 add_definitions(-D_LIBCPP_BUILDING_LIBRARY)
 
 # Warning flags ===============================================================
@@ -455,6 +457,14 @@ config_define_if(LIBCXX_HAS_PTHREAD_API _LIBCPP_HAS_THREAD_API_PTHREAD)
 config_define_if(LIBCXX_HAS_EXTERNAL_THREAD_API _LIBCPP_HAS_THREAD_API_EXTERNAL)
 config_define_if(LIBCXX_HAS_MUSL_LIBC _LIBCPP_HAS_MUSL_LIBC)
 
+# By default libc++ on Windows expects to use a shared library, which requires
+# the headers to use DLL import/export semantics. However when building a
+# static library only we modify the headers to disable DLL import/export.
+if (DEFINED WIN32 AND LIBCXX_ENABLE_STATIC AND NOT LIBCXX_ENABLE_SHARED)
+  message(STATUS "Generating custom __config for non-DLL Windows build")
+  config_define(ON _LIBCPP_DISABLE_DLL_IMPORT_EXPORT)
+endif()
+
 if (LIBCXX_NEEDS_SITE_CONFIG)
   configure_file(
     include/__config_site.in
diff --git a/libcxx/include/__config b/libcxx/include/__config
index 9f90a5bd3972..b0a3091e497b 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -519,20 +519,20 @@ namespace std {
 
 
 #ifdef _WIN32
-// only really useful for a DLL. _LIBCPP_DLL should be a compiler builtin define ideally...
-#if defined(_LIBCPP_DLL) && defined(cxx_EXPORTS)
-# define _LIBCPP_DLL_VIS __declspec(dllexport)
-# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
-# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS _LIBCPP_DLL_VIS
-#elif defined(_LIBCPP_DLL)
-# define _LIBCPP_DLL_VIS __declspec(dllimport)
-# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
-# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-#else
+#if defined(_LIBCPP_DISABLE_DLL_IMPORT_EXPORT)
 # define _LIBCPP_DLL_VIS
 # define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
 # define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+#elif defined(_LIBCPP_BUILDING_LIBRARY)
+# define _LIBCPP_DLL_VIS __declspec(dllexport)
+# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS
+# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS _LIBCPP_DLL_VIS
+#else
+# define _LIBCPP_DLL_VIS __declspec(dllimport)
+# define _LIBCPP_EXTERN_TEMPLATE_TYPE_VIS _LIBCPP_DLL_VIS
+# define _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
 #endif
+
 #define _LIBCPP_TYPE_VIS            _LIBCPP_DLL_VIS
 #define _LIBCPP_FUNC_VIS            _LIBCPP_DLL_VIS
 #define _LIBCPP_EXCEPTION_ABI       _LIBCPP_DLL_VIS
diff --git a/libcxx/include/__config_site.in b/libcxx/include/__config_site.in
index dce30bc3921c..ba0e8bee29c2 100644
--- a/libcxx/include/__config_site.in
+++ b/libcxx/include/__config_site.in
@@ -21,5 +21,6 @@
 #cmakedefine _LIBCPP_HAS_MUSL_LIBC
 #cmakedefine _LIBCPP_HAS_THREAD_API_PTHREAD
 #cmakedefine _LIBCPP_HAS_THREAD_API_EXTERNAL
+#cmakedefine _LIBCPP_DISABLE_DLL_IMPORT_EXPORT
 
 #endif // _LIBCPP_CONFIG_SITE