diff --git a/CMakeLists.txt b/CMakeLists.txt
index 563d40ee88540..54597829e7218 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1043,6 +1043,14 @@ elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "ANDROID")
   set(SWIFT_PRIMARY_VARIANT_SDK_default  "${SWIFT_HOST_VARIANT_SDK}")
   set(SWIFT_PRIMARY_VARIANT_ARCH_default "${SWIFT_HOST_VARIANT_ARCH}")
 
+elseif("${SWIFT_HOST_VARIANT_SDK}" STREQUAL "WASI")
+  set(SWIFT_HOST_VARIANT "wasi" CACHE STRING
+      "Deployment OS for Swift host tools (the compiler) [wasi]")
+
+  configure_sdk_unix("WASI" "wasm32")
+  set(SWIFT_PRIMARY_VARIANT_SDK_default  "${SWIFT_HOST_VARIANT_SDK}")
+  set(SWIFT_PRIMARY_VARIANT_ARCH_default "${SWIFT_HOST_VARIANT_ARCH}")
+
 elseif("${SWIFT_HOST_VARIANT_SDK}" MATCHES "(OSX|IOS*|TVOS*|WATCHOS*)")
 
   set(SWIFT_HOST_VARIANT "macosx" CACHE STRING
diff --git a/utils/build-script-impl b/utils/build-script-impl
index f3941c1427948..457a7077905ae 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -481,6 +481,7 @@ function verify_host_is_supported() {
       | watchsimulator-arm64    \
       | watchos-armv7k          \
       | watchos-arm64_32        \
+      | wasi-wasm32             \
       | android-armv7           \
       | android-aarch64         \
       | android-x86_64)