diff --git a/runtime_tests/lambda/stream-mock.ts b/runtime_tests/lambda/stream-mock.ts
new file mode 100644
index 000000000..9baac045f
--- /dev/null
+++ b/runtime_tests/lambda/stream-mock.ts
@@ -0,0 +1,43 @@
+import { Writable } from 'node:stream'
+import { vi } from 'vitest'
+import type {
+  APIGatewayProxyEvent,
+  APIGatewayProxyEventV2,
+} from '../../src/adapter/aws-lambda/handler'
+import type { LambdaContext } from '../../src/adapter/aws-lambda/types'
+
+type StreamifyResponseHandler = (
+  handlerFunc: (
+    event: APIGatewayProxyEvent | APIGatewayProxyEventV2,
+    responseStream: Writable,
+    context: LambdaContext
+  ) => Promise<void>
+) => (event: APIGatewayProxyEvent, context: LambdaContext) => Promise<NodeJS.WritableStream>
+
+const mockStreamifyResponse: StreamifyResponseHandler = (handlerFunc) => {
+  return async (event, context) => {
+    const chunks = []
+    const mockWritableStream = new Writable({
+      write(chunk, encoding, callback) {
+        chunks.push(chunk)
+        callback()
+      },
+    })
+    mockWritableStream.chunks = chunks
+    await handlerFunc(event, mockWritableStream, context)
+    mockWritableStream.end()
+    return mockWritableStream
+  }
+}
+
+const awslambda = {
+  streamifyResponse: mockStreamifyResponse,
+  HttpResponseStream: {
+    from: (stream: Writable, httpResponseMetadata: unknown): Writable => {
+      stream.write(Buffer.from(JSON.stringify(httpResponseMetadata)))
+      return stream
+    },
+  },
+}
+
+vi.stubGlobal('awslambda', awslambda)
diff --git a/runtime_tests/lambda/stream.test.ts b/runtime_tests/lambda/stream.test.ts
new file mode 100644
index 000000000..f4108b8ba
--- /dev/null
+++ b/runtime_tests/lambda/stream.test.ts
@@ -0,0 +1,75 @@
+import { streamHandle } from '../../src/adapter/aws-lambda/handler'
+import type { LambdaEvent } from '../../src/adapter/aws-lambda/handler'
+import type {
+  ApiGatewayRequestContext,
+  ApiGatewayRequestContextV2,
+  LambdaContext,
+} from '../../src/adapter/aws-lambda/types'
+import { Hono } from '../../src/hono'
+import './stream-mock'
+
+type Bindings = {
+  event: LambdaEvent
+  lambdaContext: LambdaContext
+  requestContext: ApiGatewayRequestContext | ApiGatewayRequestContextV2
+}
+
+const testApiGatewayRequestContextV2 = {
+  accountId: '123456789012',
+  apiId: 'urlid',
+  authentication: null,
+  authorizer: {
+    iam: {
+      accessKey: 'AKIA...',
+      accountId: '111122223333',
+      callerId: 'AIDA...',
+      cognitoIdentity: null,
+      principalOrgId: null,
+      userArn: 'arn:aws:iam::111122223333:user/example-user',
+      userId: 'AIDA...',
+    },
+  },
+  domainName: 'example.com',
+  domainPrefix: '<url-id>',
+  http: {
+    method: 'GET',
+    path: '/my/path',
+    protocol: 'HTTP/1.1',
+    sourceIp: '123.123.123.123',
+    userAgent: 'agent',
+  },
+  requestId: 'id',
+  routeKey: '$default',
+  stage: '$default',
+  time: '12/Mar/2020:19:03:58 +0000',
+  timeEpoch: 1583348638390,
+  customProperty: 'customValue',
+}
+
+describe('streamHandle function', () => {
+  const app = new Hono<{ Bindings: Bindings }>()
+
+  app.get('/cookies', async (c) => {
+    c.res.headers.append('Set-Cookie', 'cookie1=value1')
+    c.res.headers.append('Set-Cookie', 'cookie2=value2')
+    return c.text('Cookies Set')
+  })
+
+  const handler = streamHandle(app)
+
+  it('to write multiple cookies into the headers', async () => {
+    const event = {
+      headers: { 'content-type': 'text/plain' },
+      rawPath: '/cookies',
+      rawQueryString: '',
+      body: null,
+      isBase64Encoded: false,
+      requestContext: testApiGatewayRequestContextV2,
+    }
+
+    const stream = await handler(event)
+
+    const metadata = JSON.parse(stream.chunks[0].toString())
+    expect(metadata.cookies).toEqual(['cookie1=value1', 'cookie2=value2'])
+  })
+})
diff --git a/runtime_tests/lambda/vitest.config.ts b/runtime_tests/lambda/vitest.config.ts
index f030cf410..01caae52b 100644
--- a/runtime_tests/lambda/vitest.config.ts
+++ b/runtime_tests/lambda/vitest.config.ts
@@ -9,7 +9,11 @@ export default defineConfig({
     },
     globals: true,
     include: ['**/runtime_tests/lambda/**/*.+(ts|tsx|js)'],
-    exclude: ['**/runtime_tests/lambda/vitest.config.ts', '**/runtime_tests/lambda/mock.ts'],
+    exclude: [
+      '**/runtime_tests/lambda/vitest.config.ts',
+      '**/runtime_tests/lambda/mock.ts',
+      '**/runtime_tests/lambda/stream-mock.ts',
+    ],
     coverage: {
       ...config.test?.coverage,
       reportsDirectory: './coverage/raw/runtime-lambda',
diff --git a/src/adapter/aws-lambda/handler.ts b/src/adapter/aws-lambda/handler.ts
index efb85eede..4a5cfdadb 100644
--- a/src/adapter/aws-lambda/handler.ts
+++ b/src/adapter/aws-lambda/handler.ts
@@ -126,10 +126,21 @@ export const streamHandle = <
           context,
         })
 
+        const headers: Record<string, string> = {}
+        const cookies: string[] = []
+        res.headers.forEach((value, name) => {
+          if (name === 'set-cookie') {
+            cookies.push(value)
+          } else {
+            headers[name] = value
+          }
+        })
+
         // Check content type
         const httpResponseMetadata = {
           statusCode: res.status,
-          headers: Object.fromEntries(res.headers.entries()),
+          headers,
+          cookies,
         }
 
         // Update response stream