diff --git a/eslint.config.js b/eslint.config.js
index 2e6d63d..ec00836 100644
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -23,6 +23,10 @@ export default antfu({
         name: ['*', 'bytes'],
         message: 'Request/Blob/Response/... .bytes is not widely supported, use readAsBuffer instead',
       },
+      {
+        name: ['*', 'throwIfAborted'],
+        message: 'React Native\'s AbortSignal polyfill has no throwIfAborted, use throwIfAborted from @standard-server/shared instead',
+      },
     ],
   },
 }, {
diff --git a/packages/peer/src/client.ts b/packages/peer/src/client.ts
index e6a4d12..b273bb1 100644
--- a/packages/peer/src/client.ts
+++ b/packages/peer/src/client.ts
@@ -2,7 +2,7 @@ import type { StandardBody, StandardLazyResponse, StandardRequest } from '@stand
 import type { Queue } from '@standard-server/shared'
 import type { ClientPeerSendMessage, PeerEventStreamMessage, PeerOctetStreamMessage, ServerPeerSendMessage } from './types'
 import { cancelStandardBody } from '@standard-server/core'
-import { AbortError, hasAnyDefinedValue, isAsyncIteratorObject, SequentialIdGenerator } from '@standard-server/shared'
+import { AbortError, hasAnyDefinedValue, isAsyncIteratorObject, SequentialIdGenerator, throwIfAborted } from '@standard-server/shared'
 import { encodeAtomicStandardBody, toStandardBody } from './body'
 import { EventStreamTransmitter } from './event-stream'
 import { OctetStreamTransmitter } from './octet-stream'
@@ -32,7 +32,7 @@ export class ClientPeer {
   request(request: StandardRequest): Promise<StandardLazyResponse> {
     return new Promise<StandardLazyResponse>((resolve, reject) => {
       const signal = request.signal
-      signal?.throwIfAborted()
+      throwIfAborted(signal)
 
       const id = this.idGenerator.generate()
       const state: ClientPeerRequestStateInternal = { resolve, reject }
@@ -69,7 +69,7 @@ export class ClientPeer {
       const encodedAtomicBody = await encodeAtomicStandardBody(request.body, request.headers)
 
       // signal can be aborted during encode
-      request.signal?.throwIfAborted()
+      throwIfAborted(request.signal)
 
       // the peer can be closed during encode
       if (this.requests.get(id) !== state) {
diff --git a/packages/shared/src/index.ts b/packages/shared/src/index.ts
index 268349c..e7d1f23 100644
--- a/packages/shared/src/index.ts
+++ b/packages/shared/src/index.ts
@@ -8,6 +8,7 @@ export * from './object'
 export * from './promise'
 export * from './proxy'
 export * from './queue'
+export { throwIfAborted } from './signal'
 export * from './time'
 export * from './types'
 export * from './uri'
diff --git a/packages/shared/src/signal.test.ts b/packages/shared/src/signal.test.ts
index 93feebc..07d17b4 100644
--- a/packages/shared/src/signal.test.ts
+++ b/packages/shared/src/signal.test.ts
@@ -1,5 +1,5 @@
 import { describe, expect, it, vi } from 'vitest'
-import { anyAbortSignal } from './signal'
+import { anyAbortSignal, throwIfAborted } from './signal'
 
 /**
  * Helper to temporarily disable AbortSignal.any to force fallback implementation.
@@ -105,3 +105,18 @@ describe('anyAbortSignal', () => {
     })
   })
 })
+
+describe('throwIfAborted', () => {
+  it('works on a signal without throwIfAborted (React Native polyfill)', () => {
+    const controller = new AbortController()
+    Object.defineProperty(controller.signal, 'throwIfAborted', { value: undefined })
+
+    expect(() => throwIfAborted(undefined)).not.toThrow()
+    expect(() => throwIfAborted(controller.signal)).not.toThrow()
+
+    const reason = new Error('aborted')
+    controller.abort(reason)
+
+    expect(() => throwIfAborted(controller.signal)).toThrow(reason)
+  })
+})
diff --git a/packages/shared/src/signal.ts b/packages/shared/src/signal.ts
index 5f41fc4..b9f59c3 100644
--- a/packages/shared/src/signal.ts
+++ b/packages/shared/src/signal.ts
@@ -43,3 +43,13 @@ export function anyAbortSignal(...signals: (AbortSignal | undefined)[]): AbortSi
 
   return controller.signal
 }
+
+/**
+ * Throws the signal's abort reason if it is aborted, like `signal.throwIfAborted()`.
+ * React Native's AbortSignal polyfill has no `throwIfAborted`, so use this instead.
+ */
+export function throwIfAborted(signal: AbortSignal | undefined | null): void {
+  if (signal?.aborted) {
+    throw signal.reason
+  }
+}
diff --git a/packages/shared/src/time.ts b/packages/shared/src/time.ts
index 7c4f197..fbfa313 100644
--- a/packages/shared/src/time.ts
+++ b/packages/shared/src/time.ts
@@ -1,3 +1,5 @@
+import { throwIfAborted } from './signal'
+
 export interface SleepOptions {
   signal?: AbortSignal | undefined
 }
@@ -7,10 +9,7 @@ export interface SleepOptions {
  */
 export function sleep(ms: number, { signal }: SleepOptions = {}): Promise<void> {
   return new Promise((resolve, reject) => {
-    if (signal?.aborted) {
-      reject(signal.reason)
-      return
-    }
+    throwIfAborted(signal)
 
     let abortListener: (() => void) | null = null
 
diff --git a/tests/client-server.node-http2.ts b/tests/client-server.node-http2.ts
index de1117d..e5d00fb 100644
--- a/tests/client-server.node-http2.ts
+++ b/tests/client-server.node-http2.ts
@@ -5,6 +5,7 @@ import * as http2 from 'node:http2'
 import { Readable } from 'node:stream'
 import { toFetchBody, toFetchHeaders, toStandardLazyResponse } from '@standard-server/fetch'
 import { sendStandardResponse, toStandardLazyRequest } from '@standard-server/node'
+import { throwIfAborted } from '@standard-server/shared'
 import { generateTlsCert } from './tls'
 
 export interface NodeHttp2ClientServerTestOptions {
@@ -57,7 +58,7 @@ export function createNodeHttp2ClientServerTest(options: NodeHttp2ClientServerTe
   })
 
   const request: ClientServerTest['request'] = vi.fn(async (standardRequest) => {
-    standardRequest.signal?.throwIfAborted()
+    throwIfAborted(standardRequest.signal)
 
     const { session, port } = await serverReady
 
diff --git a/tests/client-server.node-https.ts b/tests/client-server.node-https.ts
index 724662a..b57ad88 100644
--- a/tests/client-server.node-https.ts
+++ b/tests/client-server.node-https.ts
@@ -5,6 +5,7 @@ import * as https from 'node:https'
 import { Readable } from 'node:stream'
 import { toFetchBody, toFetchHeaders, toStandardLazyResponse } from '@standard-server/fetch'
 import { sendStandardResponse, toStandardLazyRequest } from '@standard-server/node'
+import { throwIfAborted } from '@standard-server/shared'
 import { generateTlsCert } from './tls'
 
 export function createNodeHttpsClientServerTest(): ClientServerTest {
@@ -39,7 +40,7 @@ export function createNodeHttpsClientServerTest(): ClientServerTest {
   })
 
   const request: ClientServerTest['request'] = vi.fn(async (standardRequest) => {
-    standardRequest.signal?.throwIfAborted()
+    throwIfAborted(standardRequest.signal)
 
     const { agent, port } = await serverReady