diff --git a/index.d.ts b/index.d.ts
index cf7dd3e..0e90aa7 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -70,7 +70,7 @@ export type Reviver = (k: number | string, v: unknown) => unknown
  */
 export function parse(
   json: string,
-  reviver?: Reviver,
+  reviver?: Reviver | null,
   removesComments?: boolean
 ): CommentJSONValue