diff --git a/src/serve/server-threads.ts b/src/serve/server-threads.ts
index 273f801..0d2e05f 100644
--- a/src/serve/server-threads.ts
+++ b/src/serve/server-threads.ts
@@ -1,5 +1,8 @@
 import { closeSync, openSync } from 'node:fs';
+import { platform } from 'node:process';
 import type { Server } from 'node:net';
+
+const fdPath = (fd: number) => (platform === 'linux' ? `/proc/self/fd/${fd}` : `/dev/fd/${fd}`);
 import { channel } from '../channel.ts';
 import { shared } from '../shared/shared.ts';
 import { int32atomic } from '../shared/descriptors.ts';
@@ -50,7 +53,7 @@ export function serverThreads(
     // event loop tracking. This lets socket.destroy() properly close the
     // original fd (freeing libuv state) while the dup'd fd survives for the
     // worker to open as a fresh Socket.
-    const fd = openSync(`/dev/fd/${origFd}`, 'r+');
+    const fd = openSync(fdPath(origFd), 'r+');
     socket.destroy();
 
     counters.elements[idx].add(1);
diff --git a/test/serve/listen.test.ts b/test/serve/listen.test.ts
index 2143693..8ae7077 100644
--- a/test/serve/listen.test.ts
+++ b/test/serve/listen.test.ts
@@ -2,7 +2,10 @@ import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import { once } from 'node:events';
 import { openSync } from 'node:fs';
+import { platform } from 'node:process';
 import { createServer as createNetServer, connect } from 'node:net';
+
+const fdPath = (fd: number) => (platform === 'linux' ? `/proc/self/fd/${fd}` : `/dev/fd/${fd}`);
 import { createServer } from 'node:http';
 import { int32atomic } from 'moroutine';
 import { Int32Atomic } from '../../src/shared/int32-atomic.ts';
@@ -20,7 +23,7 @@ async function acquireLocalFd(): Promise<{ fd: number; close: () => void }> {
   const client = connect(port);
   const [peer] = (await once(srv, 'connection')) as [any];
   const origFd: number = peer._handle.fd;
-  const fd = openSync(`/dev/fd/${origFd}`, 'r+'); // dup — new fd, not tracked by libuv
+  const fd = openSync(fdPath(origFd), 'r+'); // dup — new fd, not tracked by libuv
   peer.pause();
   peer._handle = null;
   peer.destroy();
diff --git a/test/serve/spike.test.ts b/test/serve/spike.test.ts
index aa78dc2..3c424af 100644
--- a/test/serve/spike.test.ts
+++ b/test/serve/spike.test.ts
@@ -2,7 +2,10 @@ import { describe, it } from 'node:test';
 import assert from 'node:assert/strict';
 import { once } from 'node:events';
 import { openSync } from 'node:fs';
+import { platform } from 'node:process';
 import { createServer, connect } from 'node:net';
+
+const fdPath = (fd: number) => (platform === 'linux' ? `/proc/self/fd/${fd}` : `/dev/fd/${fd}`);
 import { Worker } from 'node:worker_threads';
 
 describe('fd-passing spike', () => {
@@ -24,7 +27,7 @@ describe('fd-passing spike', () => {
     const server = createServer();
     server.on('connection', (socket) => {
       // Dup the fd via /dev/fd so the new descriptor is independent of libuv.
-      const fd = openSync(`/dev/fd/${(socket as any)._handle.fd}`, 'r+');
+      const fd = openSync(fdPath((socket as any)._handle.fd), 'r+');
       socket.destroy();
       worker.postMessage({ fd });
     });