diff --git a/.changeset/wild-ladybugs-flash.md b/.changeset/wild-ladybugs-flash.md
new file mode 100644
index 0000000000..e683b78d9b
--- /dev/null
+++ b/.changeset/wild-ladybugs-flash.md
@@ -0,0 +1,5 @@
+---
+'@lit-labs/ssr': patch
+---
+
+Use `url` module to parse file URL to path for Windows compatibility
diff --git a/packages/labs/ssr/src/lib/module-loader.ts b/packages/labs/ssr/src/lib/module-loader.ts
index eb233bf538..b6b6e00e3a 100644
--- a/packages/labs/ssr/src/lib/module-loader.ts
+++ b/packages/labs/ssr/src/lib/module-loader.ts
@@ -131,7 +131,7 @@ export class ModuleLoader {
     if (moduleURL.protocol !== 'file:') {
       throw new Error(`Unsupported protocol: ${moduleURL.protocol}`);
     }
-    const modulePath = moduleURL.pathname;
+    const modulePath = fileURLToPath(moduleURL);
 
     // Look in the cache
     let moduleRecord = this.cache.get(modulePath);