diff --git a/packages/remix-server-runtime/single-fetch.ts b/packages/remix-server-runtime/single-fetch.ts
index e9298122a7b..bbe42a1cac7 100644
--- a/packages/remix-server-runtime/single-fetch.ts
+++ b/packages/remix-server-runtime/single-fetch.ts
@@ -377,7 +377,7 @@ type DataFunctionReturnValue =
 export type Serialize<T extends Loader | Action> =
   Awaited<ReturnType<T>> extends TypedDeferredData<infer D> ? D :
   Awaited<ReturnType<T>> extends TypedResponse<Record<string, unknown>> ? SerializeFrom<T> :
-  Awaited<ReturnType<T>> extends DataWithResponseInit<infer D> ? D :
+  Awaited<ReturnType<T>> extends DataWithResponseInit<infer D> | Serializable ? D :
   Awaited<ReturnType<T>>;
 
 export type Loader = (