diff --git a/src/fetch.ts b/src/fetch.ts
index 214593ec..4ddbf7a6 100644
--- a/src/fetch.ts
+++ b/src/fetch.ts
@@ -33,10 +33,10 @@ export interface FetchOptions<R extends ResponseType = ResponseType> extends Omi
   response?: boolean
   retry?: number | false
 
-  onRequest?(ctx: FetchContext): Promise<void>
-  onRequestError?(ctx: FetchContext & { error: Error }): Promise<void>
-  onResponse?(ctx: FetchContext & { response: FetchResponse<R> }): Promise<void>
-  onResponseError?(ctx: FetchContext & { response: FetchResponse<R> }): Promise<void>
+  onRequest?(ctx: FetchContext): Promise<void> | void
+  onRequestError?(ctx: FetchContext & { error: Error }): Promise<void> | void
+  onResponse?(ctx: FetchContext & { response: FetchResponse<R> }): Promise<void> | void
+  onResponseError?(ctx: FetchContext & { response: FetchResponse<R> }): Promise<void> | void
 }
 
 export interface $Fetch {