diff --git a/test/types/mock-interceptor.test-d.ts b/test/types/mock-interceptor.test-d.ts
index deb3c50c6f0..b3c939aecf9 100644
--- a/test/types/mock-interceptor.test-d.ts
+++ b/test/types/mock-interceptor.test-d.ts
@@ -1,7 +1,11 @@
 import { expectAssignable } from 'tsd'
-import { MockAgent, MockPool } from '../..'
+import { MockAgent, MockPool, BodyInit, Dispatcher } from '../..'
 import { MockInterceptor, MockScope } from '../../types/mock-interceptor'
 
+declare const mockResponseCallbackOptions: MockInterceptor.MockResponseCallbackOptions;
+
+expectAssignable<BodyInit | Dispatcher.DispatchOptions['body']>(mockResponseCallbackOptions.body)
+
 {
   const mockPool: MockPool = new MockAgent().get('')
   const mockInterceptor = mockPool.intercept({ path: '', method: 'GET' })
diff --git a/types/mock-interceptor.d.ts b/types/mock-interceptor.d.ts
index 2e4272176ad..88d38032ae2 100644
--- a/types/mock-interceptor.d.ts
+++ b/types/mock-interceptor.d.ts
@@ -1,6 +1,6 @@
 import { IncomingHttpHeaders } from 'http'
 import Dispatcher from './dispatcher';
-import { Headers } from './fetch'
+import { BodyInit, Headers } from './fetch'
 
 export {
   Interceptable,
@@ -71,7 +71,7 @@ declare namespace MockInterceptor {
     path: string;
     origin: string;
     method: string;
-    body?: string;
+    body?: BodyInit | Dispatcher.DispatchOptions['body'];
     headers: Headers;
     maxRedirections: number;
   }