diff --git a/src/legacy/classes/GraphQLClient.ts b/src/legacy/classes/GraphQLClient.ts
index adade7813..bf844163c 100644
--- a/src/legacy/classes/GraphQLClient.ts
+++ b/src/legacy/classes/GraphQLClient.ts
@@ -75,7 +75,7 @@ export class GraphQLClient {
     })
 
     if (responseMiddleware) {
-      responseMiddleware(response, {
+      await responseMiddleware(response, {
         operationName: document.operationName,
         variables,
         url: this.url,
@@ -146,7 +146,7 @@ export class GraphQLClient {
     })
 
     if (responseMiddleware) {
-      responseMiddleware(response, {
+      await responseMiddleware(response, {
         operationName: analyzedDocument.operationName,
         variables: requestOptions.variables,
         url: this.url,
@@ -222,7 +222,7 @@ export class GraphQLClient {
     })
 
     if (this.requestConfig.responseMiddleware) {
-      this.requestConfig.responseMiddleware(response, {
+      await this.requestConfig.responseMiddleware(response, {
         operationName: undefined,
         variables,
         url: this.url,
diff --git a/src/legacy/helpers/types.ts b/src/legacy/helpers/types.ts
index ef46d3427..c440a9dff 100644
--- a/src/legacy/helpers/types.ts
+++ b/src/legacy/helpers/types.ts
@@ -1,7 +1,7 @@
 import type { TypedDocumentNode } from '@graphql-typed-document-node/core'
 import type { GraphQLError } from 'graphql/error/GraphQLError.js'
 import type { DocumentNode } from 'graphql/language/ast.js'
-import type { MaybeLazy, RemoveIndex } from '../../lib/prelude.js'
+import type { MaybeLazy, MaybePromise, RemoveIndex } from '../../lib/prelude.js'
 import type { ClientError } from '../classes/ClientError.js'
 
 export type Fetch = typeof fetch
@@ -93,7 +93,7 @@ export type RequestOptions<V extends Variables = Variables, T = unknown> =
 export type ResponseMiddleware = (
   response: GraphQLClientResponse<unknown> | ClientError | Error,
   request: RequestExtendedInit,
-) => void
+) => MaybePromise<void>
 
 export type RequestMiddleware<V extends Variables = Variables> = (
   request: RequestExtendedInit<V>,
diff --git a/src/lib/prelude.ts b/src/lib/prelude.ts
index 78832225c..3f8f04201 100644
--- a/src/lib/prelude.ts
+++ b/src/lib/prelude.ts
@@ -247,3 +247,5 @@ export function assertObject(v: unknown): asserts v is object {
 }
 
 export type StringKeyof<T> = keyof T & string
+
+export type MaybePromise<T> = T | Promise<T>
diff --git a/tests/legacy/middleware.test.ts b/tests/legacy/middleware.test.ts
new file mode 100644
index 000000000..3a3d9bc8c
--- /dev/null
+++ b/tests/legacy/middleware.test.ts
@@ -0,0 +1,16 @@
+import { expect, test } from 'vitest'
+import { GraphQLClient } from '../../src/entrypoints/main.js'
+import { setupMockServer } from './__helpers.js'
+
+const ctx = setupMockServer()
+
+test(`throwing an error in response middleware is not swalled`, async () => {
+  const client = new GraphQLClient(ctx.url, {
+    // eslint-disable-next-line
+    responseMiddleware: async () => {
+      throw new Error(`TEST ERROR`)
+    },
+  })
+  ctx.res()
+  await expect(client.request(`{ me { id } }`)).rejects.toMatchInlineSnapshot(`[Error: TEST ERROR]`)
+})