diff --git a/scripts/test-gateway.mjs b/scripts/test-gateway.mjs
index 313e35d6..83fff12c 100644
--- a/scripts/test-gateway.mjs
+++ b/scripts/test-gateway.mjs
@@ -73,12 +73,22 @@ export function resolveComposeNetworkName(rootDir, env = process.env) {
   return `${resolveComposeProjectName(rootDir, env)}_default`;
 }
 
+function usesWindowsPathSyntax(filePath) {
+  return /^[A-Za-z]:[\\/]/.test(filePath) || filePath.startsWith("\\\\");
+}
+
+function pathForInputs(...filePaths) {
+  return filePaths.some((filePath) => usesWindowsPathSyntax(String(filePath || ""))) ? path.win32 : path;
+}
+
 export function resolveConfigDirectory(rootDir, explicitDir = null) {
+  const pathModule = pathForInputs(rootDir, explicitDir);
+
   if (explicitDir) {
-    return path.resolve(rootDir, explicitDir);
+    return pathModule.resolve(rootDir, explicitDir);
   }
 
-  return path.join(rootDir, ".tmp", "test-gateway");
+  return pathModule.join(rootDir, ".tmp", "test-gateway");
 }
 
 export function shouldClaimGateway(existingConfig = {}, installToken = "") {