diff --git a/Runtimes/Overlay/Windows/CRT/CMakeLists.txt b/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
index 09f0a3f6084bd..0c67c3f5fd683 100644
--- a/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/CRT/CMakeLists.txt
@@ -14,6 +14,7 @@ target_compile_definitions(swiftCRT PRIVATE
 target_compile_options(swiftCRT PRIVATE
   "SHELL:-Xcc -D_USE_MATH_DEFINES")
 target_link_libraries(swiftCRT PRIVATE
+  ClangModules
   swiftCore)
 
 install(TARGETS swiftCRT
diff --git a/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt b/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
index b31759a30e896..9140c71e0261f 100644
--- a/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/WinSDK/CMakeLists.txt
@@ -6,6 +6,7 @@ set_target_properties(swiftWinSDK PROPERTIES
 target_compile_definitions(swiftCRT PRIVATE
   $<$<BOOL:${SwiftOverlay_ENABLE_REFLECTION}>:SWIFT_ENABLE_REFLECTION>)
 target_link_libraries(swiftWinSDK PRIVATE
+  ClangModules
   swiftCore)
 
 install(TARGETS swiftWinSDK
diff --git a/Runtimes/Overlay/Windows/clang/CMakeLists.txt b/Runtimes/Overlay/Windows/clang/CMakeLists.txt
index 4e8489cb822e9..8f2872d1c8ce1 100644
--- a/Runtimes/Overlay/Windows/clang/CMakeLists.txt
+++ b/Runtimes/Overlay/Windows/clang/CMakeLists.txt
@@ -1,4 +1,46 @@
 
+file(TO_CMAKE_PATH "$ENV{WindowsSdkDir}" WindowsSdkDir)
+file(TO_CMAKE_PATH "$ENV{WindowsSDKVersion}" WindowsSDKVersion)
+file(TO_CMAKE_PATH "$ENV{UniversalCRTSdkDir}" UniversalCRTSdkDir)
+file(TO_CMAKE_PATH "$ENV{UCRTVersion}" UCRTVersion)
+file(TO_CMAKE_PATH "$ENV{VCToolsInstallDir}" VCToolsInstallDir)
+
+file(CONFIGURE
+  OUTPUT windows-sdk-overlay.yaml
+  CONTENT [[
+---
+version: 0
+case-sensitive: false
+use-external-names: false
+roots:
+  - name: "@WindowsSdkDir@/Include/@WindowsSDKVersion@/um"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/winsdk.modulemap"
+  - name: "@UniversalCRTSdkDir@/Include/@UCRTVersion@/ucrt"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/ucrt.modulemap"
+  - name: "@VCToolsInstallDir@include"
+    type: directory
+    contents:
+      - name: module.modulemap
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/vcruntime.modulemap"
+      - name: vcruntime.apinotes
+        type: file
+        external-contents: "@CMAKE_CURRENT_SOURCE_DIR@/vcruntime.apinotes"
+]]
+ESCAPE_QUOTES @ONLY NEWLINE_STYLE LF)
+
+add_library(ClangModules INTERFACE)
+target_compile_options(ClangModules INTERFACE
+  "$<$<COMPILE_LANGUAGE:Swift>:SHELL:-vfsoverlay ${CMAKE_CURRENT_BINARY_DIR}/windows-sdk-overlay.yaml>")
+
 install(FILES
   ucrt.modulemap
   vcruntime.apinotes
diff --git a/Runtimes/Overlay/clang/CMakeLists.txt b/Runtimes/Overlay/clang/CMakeLists.txt
index 74e57f0480d1f..c1c91ad2ea126 100644
--- a/Runtimes/Overlay/clang/CMakeLists.txt
+++ b/Runtimes/Overlay/clang/CMakeLists.txt
@@ -9,6 +9,7 @@ set_target_properties(swift_Builtin_float PROPERTIES
 target_compile_options(swift_Builtin_float PRIVATE
   "$<$<PLATFORM_ID:Darwin>:SHELL:-Xfrontend -module-abi-name -Xfrontend Darwin>")
 target_link_libraries(swift_Builtin_float PRIVATE
+  $<$<PLATFORM_ID:Windows>:ClangModules>
   swiftCore)
 
 install(TARGETS swift_Builtin_float