diff --git a/infra/release-build.sh b/infra/release-build.sh
index 15d2af5..637de8a 100755
--- a/infra/release-build.sh
+++ b/infra/release-build.sh
@@ -71,6 +71,7 @@ sign_and_notarize_binary () {
   return
 }
 
+EXT=
 case "${OS}" in
 macos)
   TARGETS=(
@@ -88,6 +89,7 @@ windows)
   TARGETS=(
     //cmd/engflow_auth:engflow_auth_windows_x64
   )
+  EXT=.exe
   ;;
 esac
 
@@ -104,5 +106,5 @@ trap uninstall_cert EXIT
 for target in "${TARGETS[@]}"; do
   target_file=$(bazel cquery --output=files "${target}")
   sign_and_notarize_binary "${target_file}"
-  cp "${target_file}" _out/
+  cp "${target_file}" "_out/${target_file}${EXT}"
 done