diff --git a/apps/nest-node-probe/correctness/set-immediate.ts b/apps/nest-node-probe/correctness/set-immediate.ts
new file mode 100644
index 0000000..7b02a79
--- /dev/null
+++ b/apps/nest-node-probe/correctness/set-immediate.ts
@@ -0,0 +1,33 @@
+import { setImmediate as setImmediateFromTimers } from 'node:timers'
+
+const log = (line: string): void => {
+  console.log(line)
+}
+
+log('start')
+const a = setImmediate(() => {
+  log('immediate a')
+  setImmediate(() => log('immediate queued by a (next turn)'))
+  process.nextTick(() => log('tick from a'))
+  Promise.resolve().then(() => log('microtask from a'))
+})
+setImmediate(() => log('immediate b'))
+const c = setImmediate(() => log('immediate c (cleared)'))
+clearImmediate(c)
+log(`hasRef ${a.hasRef()} ${a.unref().hasRef()} ${a.ref().hasRef()}`)
+setTimeout(() => {
+  log('timer 10ms')
+  setImmediate(() => log('immediate from timer'))
+  setTimeout(() => log('timer 0 from timer'), 0)
+}, 10)
+setImmediate(() => {
+  const d = setImmediate(() => log('immediate d (cleared from immediate b2)'))
+  clearImmediate(d)
+  log('immediate b2')
+})
+setImmediateFromTimers(() => log('immediate from node:timers'))
+setTimeout(() => {
+  setImmediate(() => log('unref immediate ran')).unref()
+  log('timer 20ms, last referenced work')
+}, 20)
+log('end')
diff --git a/plugin/intrinsics.mjs b/plugin/intrinsics.mjs
index a12ac5e..c9efca1 100644
--- a/plugin/intrinsics.mjs
+++ b/plugin/intrinsics.mjs
@@ -482,6 +482,26 @@ export const intrinsics = {
     returnType: 'void',
     decl: 'void __gea_node_clear_timer(double id);'
   },
+  __gea_node_immediate_start: {
+    emit: '__gea_node_immediate_start',
+    returnType: 'double',
+    decl: 'double __gea_node_immediate_start(std::function<void()> callback);'
+  },
+  __gea_node_immediate_clear: {
+    emit: '__gea_node_immediate_clear',
+    returnType: 'void',
+    decl: 'void __gea_node_immediate_clear(double id);'
+  },
+  __gea_node_immediate_ref: {
+    emit: '__gea_node_immediate_ref',
+    returnType: 'void',
+    decl: 'void __gea_node_immediate_ref(double id);'
+  },
+  __gea_node_immediate_unref: {
+    emit: '__gea_node_immediate_unref',
+    returnType: 'void',
+    decl: 'void __gea_node_immediate_unref(double id);'
+  },
   __gea_node_process_env: {
     emit: 'gea_cpp_process_env',
     returnType: 'gea_cpp_value'
diff --git a/runtime/gea_node.cpp b/runtime/gea_node.cpp
index 3968c6a..3ca7987 100644
--- a/runtime/gea_node.cpp
+++ b/runtime/gea_node.cpp
@@ -408,6 +408,77 @@ inline void fireDue() {
 
 }  // namespace gea::node::timers
 
+namespace gea::node::immediates {
+
+struct Immediate {
+  double id;
+  bool referenced;
+  std::function<void()> callback;
+};
+
+inline std::vector<Immediate> &queue() {
+  static std::vector<Immediate> immediates;
+  return immediates;
+}
+
+inline double nextImmediateId() {
+  static double id = 0;
+  return ++id;
+}
+
+inline bool hasPending() { return !queue().empty(); }
+inline bool hasReferenced() {
+  for (const Immediate &immediate : queue())
+    if (immediate.referenced) return true;
+  return false;
+}
+
+inline double add(std::function<void()> callback) {
+  const double id = nextImmediateId();
+  queue().push_back(Immediate{id, true, std::move(callback)});
+  return id;
+}
+
+inline std::unordered_set<double> &running() {
+  static std::unordered_set<double> ids;
+  return ids;
+}
+
+inline void remove(double id) {
+  running().erase(id);
+  auto &immediates = queue();
+  immediates.erase(
+      std::remove_if(immediates.begin(), immediates.end(), [&](const Immediate &immediate) { return immediate.id == id; }),
+      immediates.end());
+}
+
+inline void setReferenced(double id, bool referenced) {
+  for (Immediate &immediate : queue()) {
+    if (immediate.id == id) {
+      immediate.referenced = referenced;
+      return;
+    }
+  }
+}
+
+inline void runAll(bool loopAlive) {
+  if (queue().empty()) return;
+  if (!loopAlive && !hasReferenced()) return;
+  std::vector<Immediate> batch;
+  batch.swap(queue());
+  gea::detail::HostCallbackScope scope;
+  running().clear();
+  for (const Immediate &immediate : batch) running().insert(immediate.id);
+  for (Immediate &immediate : batch) {
+    if (running().erase(immediate.id) == 0) continue;
+    if (immediate.callback) immediate.callback();
+    gea::node::drain_microtasks();
+  }
+  running().clear();
+}
+
+}
+
 // ---------------------------------------------------------------------------
 // Size-class free-list allocator (global operator new/delete override).
 //
@@ -1070,7 +1141,7 @@ class EventLoop {
       });
       const bool timersPending = gea::node::timers::hasPending();
       if ((pfds.empty() || (done == nullptr && !haveReferencedWatcher)) &&
-          !gea::node::timers::hasReferenced()) {
+          !gea::node::timers::hasReferenced() && !gea::node::immediates::hasReferenced()) {
         purgeClosedIfSafe();
         return stopRequested(done);  // only unref work remains
       }
@@ -1081,7 +1152,7 @@ class EventLoop {
       // times per request, re-tracing the request's live objects each time.
       gea::collectCyclesAtQuiescence();
       if (!gea::node::microtasks().empty() || !gea::node::next_ticks().empty()) continue;
-      const int timeout = timersPending ? gea::node::timers::nextDelayMs() : -1;
+      const int timeout = gea::node::immediates::hasReferenced() ? 0 : timersPending ? gea::node::timers::nextDelayMs() : -1;
       const int events = platform::poll(pfds.data(), pfds.size(), timeout);
       if (events < 0) {
         if (errno == EINTR) continue;
@@ -1116,6 +1187,7 @@ class EventLoop {
       // Handler promises progress here: continuations queued during dispatch
       // (async handlers, body-delivery microtasks) run before the next poll.
       gea::node::drain_microtasks();
+      gea::node::immediates::runAll(haveReferencedWatcher || gea::node::timers::hasReferenced());
       const bool stopped = stopRequested(done);
       --dispatchDepth_;
       purgeClosedIfSafe();
@@ -1155,14 +1227,14 @@ class EventLoop {
       });
       const bool timersPending = gea::node::timers::hasPending();
       if ((!haveWatchers || (done == nullptr && !haveReferencedWatcher)) &&
-          !gea::node::timers::hasReferenced()) {
+          !gea::node::timers::hasReferenced() && !gea::node::immediates::hasReferenced()) {
         purgeClosedIfSafe();
         return stopRequested(done);
       }
 
       gea::collectCyclesAtQuiescence();  // see `runPoll`
       if (!gea::node::microtasks().empty() || !gea::node::next_ticks().empty()) continue;
-      const int timeout = timersPending ? gea::node::timers::nextDelayMs() : -1;
+      const int timeout = gea::node::immediates::hasReferenced() ? 0 : timersPending ? gea::node::timers::nextDelayMs() : -1;
       const int count = ::epoll_wait(epollFd_, events, 128, timeout);
       if (count < 0) {
         if (errno == EINTR) continue;
@@ -1192,6 +1264,7 @@ class EventLoop {
         if (stopRequested(done)) break;
       }
       gea::node::drain_microtasks();
+      gea::node::immediates::runAll(haveReferencedWatcher || gea::node::timers::hasReferenced());
       const bool stopped = stopRequested(done);
       --dispatchDepth_;
       purgeClosedIfSafe();
@@ -1233,7 +1306,7 @@ class EventLoop {
       });
       const bool timersPending = gea::node::timers::hasPending();
       if ((!haveWatchers || (done == nullptr && !haveReferencedWatcher)) &&
-          !gea::node::timers::hasReferenced()) {
+          !gea::node::timers::hasReferenced() && !gea::node::immediates::hasReferenced()) {
         applyKqueueChanges(changes);
         purgeClosedIfSafe();
         return stopRequested(done);
@@ -1245,7 +1318,7 @@ class EventLoop {
         continue;
       }
       struct timespec wait{};
-      const int delay = timersPending ? gea::node::timers::nextDelayMs() : -1;
+      const int delay = gea::node::immediates::hasReferenced() ? 0 : timersPending ? gea::node::timers::nextDelayMs() : -1;
       if (delay >= 0) {
         wait.tv_sec = delay / 1000;
         wait.tv_nsec = static_cast<long>(delay % 1000) * 1000000L;
@@ -1300,6 +1373,7 @@ class EventLoop {
         if (stopRequested(done)) break;
       }
       gea::node::drain_microtasks();
+      gea::node::immediates::runAll(haveReferencedWatcher || gea::node::timers::hasReferenced());
       const bool stopped = stopRequested(done);
       --dispatchDepth_;
       purgeClosedIfSafe();
@@ -4055,6 +4129,17 @@ inline void __gea_node_clear_timer(double id) { gea::node::timers::remove(id); }
 
 inline void __gea_node_timer_unref(double id) { gea::node::timers::unref(id); }
 
+inline double __gea_node_immediate_start(std::function<void()> callback) {
+  if (!callback) return 0;
+  return gea::node::immediates::add(std::move(callback));
+}
+
+inline void __gea_node_immediate_clear(double id) { gea::node::immediates::remove(id); }
+
+inline void __gea_node_immediate_ref(double id) { gea::node::immediates::setReferenced(id, true); }
+
+inline void __gea_node_immediate_unref(double id) { gea::node::immediates::setReferenced(id, false); }
+
 inline void __gea_node_run_pending() { gea::node::clientEventLoop().run(); }
 
 inline bool __gea_node_pump_until(const std::function<bool()> &done) {
diff --git a/runtime/node/generated/facades/timers.ts b/runtime/node/generated/facades/timers.ts
index f9507ee..c57b752 100644
--- a/runtime/node/generated/facades/timers.ts
+++ b/runtime/node/generated/facades/timers.ts
@@ -1,16 +1,5 @@
 // Generated from the pinned Node 24 declaration inventory. Do not edit.
 // Canonical builtin: node:timers
-import { nodeNotImplemented } from "../../not-implemented"
-export { clearInterval, clearTimeout, setInterval, setTimeout } from "../../timers"
-
-export function clearImmediate(...args: unknown[]): never {
-  void args
-  return nodeNotImplemented("node:timers", "clearImmediate")
-}
+export { clearImmediate, clearInterval, clearTimeout, setImmediate, setInterval, setTimeout } from "../../timers"
 
 export const promises: unknown = undefined
-
-export function setImmediate(...args: unknown[]): never {
-  void args
-  return nodeNotImplemented("node:timers", "setImmediate")
-}
diff --git a/runtime/node/generated/node24-compatibility.json b/runtime/node/generated/node24-compatibility.json
index 22cc2ae..0cf05ca 100644
--- a/runtime/node/generated/node24-compatibility.json
+++ b/runtime/node/generated/node24-compatibility.json
@@ -18096,7 +18096,11 @@
         {
           "name": "clearImmediate",
           "kind": "function",
-          "status": "stubbed"
+          "status": "partial",
+          "overlay": "timers.ts",
+          "supportedCallSignatures": [
+            "(immediate: NodeJS.Immediate | undefined): void"
+          ]
         },
         {
           "name": "clearInterval",
@@ -18126,7 +18130,12 @@
         {
           "name": "setImmediate",
           "kind": "function",
-          "status": "stubbed"
+          "status": "partial",
+          "overlay": "timers.ts",
+          "supportedCallSignatures": [
+            "<TArgs extends any[]>(callback: (...args: TArgs) => void, ...args: TArgs): NodeJS.Immediate",
+            "(callback: (_: void) => void): NodeJS.Immediate"
+          ]
         },
         {
           "name": "setInterval",
diff --git a/runtime/node/global-timers.ts b/runtime/node/global-timers.ts
index c4dbd5a..3b6b449 100644
--- a/runtime/node/global-timers.ts
+++ b/runtime/node/global-timers.ts
@@ -44,6 +44,14 @@ declare function __gea_node_timer_start_interval(callback: () => void, delay: nu
 declare function __gea_node_timer_clear(id: number): void
 /** @gea-host-inert */
 declare function __gea_node_timer_unref(id: number): void
+/** @gea-host-no-property-writes */
+declare function __gea_node_immediate_start(callback: () => void): number
+/** @gea-host-inert */
+declare function __gea_node_immediate_clear(id: number): void
+/** @gea-host-inert */
+declare function __gea_node_immediate_ref(id: number): void
+/** @gea-host-inert */
+declare function __gea_node_immediate_unref(id: number): void
 
 class Timeout {
   private id_: number
@@ -112,3 +120,50 @@ function clearTimeout(handle: Timeout | number | null | undefined): void {
 function clearInterval(handle: Timeout | number | null | undefined): void {
   clearTimeout(handle)
 }
+
+class Immediate {
+  private id_: number
+  private referenced_: boolean
+
+  constructor(id: number) {
+    this.id_ = id
+    this.referenced_ = true
+  }
+
+  id(): number {
+    return this.id_
+  }
+
+  ref(): Immediate {
+    if (!this.referenced_) {
+      this.referenced_ = true
+      __gea_node_immediate_ref(this.id_)
+    }
+    return this
+  }
+
+  unref(): Immediate {
+    if (this.referenced_) {
+      this.referenced_ = false
+      __gea_node_immediate_unref(this.id_)
+    }
+    return this
+  }
+
+  hasRef(): boolean {
+    return this.referenced_
+  }
+}
+
+function setImmediate(callback: (...args: any[]) => void): Immediate {
+  return new Immediate(
+    __gea_node_immediate_start((): void => {
+      callback()
+    })
+  )
+}
+
+function clearImmediate(handle: Immediate | null | undefined): void {
+  if (handle === null || handle === undefined) return
+  __gea_node_immediate_clear(handle.id())
+}
diff --git a/runtime/node/node-globals.ts b/runtime/node/node-globals.ts
index 7fb11f5..b89a57d 100644
--- a/runtime/node/node-globals.ts
+++ b/runtime/node/node-globals.ts
@@ -180,6 +180,7 @@ declare global {
     // package's unrelated object graph.
     type BufferConstructor = globalThis.BufferConstructor
     type Timeout = import('./timers.js').Timeout
+    type Immediate = import('./timers.js').Immediate
     type WriteStream = import('./process.js').WriteStream
     type Platform = typeof import('./process.js').platform
 
diff --git a/runtime/node/timers.ts b/runtime/node/timers.ts
index ed432c0..82eef39 100644
--- a/runtime/node/timers.ts
+++ b/runtime/node/timers.ts
@@ -18,15 +18,23 @@
 const TimeoutAlias = Timeout
 type TimeoutAlias = Timeout
 
+const ImmediateAlias = Immediate
+type ImmediateAlias = Immediate
+
 const setTimeoutAlias = setTimeout
 const setIntervalAlias = setInterval
 const clearTimeoutAlias = clearTimeout
 const clearIntervalAlias = clearInterval
+const setImmediateAlias = setImmediate
+const clearImmediateAlias = clearImmediate
 
 export {
   TimeoutAlias as Timeout,
+  ImmediateAlias as Immediate,
   setTimeoutAlias as setTimeout,
   setIntervalAlias as setInterval,
   clearTimeoutAlias as clearTimeout,
-  clearIntervalAlias as clearInterval
+  clearIntervalAlias as clearInterval,
+  setImmediateAlias as setImmediate,
+  clearImmediateAlias as clearImmediate
 }
diff --git a/scripts/test-set-immediate.mjs b/scripts/test-set-immediate.mjs
new file mode 100644
index 0000000..47a556d
--- /dev/null
+++ b/scripts/test-set-immediate.mjs
@@ -0,0 +1,26 @@
+import assert from 'node:assert/strict'
+import { execFileSync, spawnSync } from 'node:child_process'
+import { mkdirSync } from 'node:fs'
+import { resolve } from 'node:path'
+
+const root = resolve(import.meta.dirname, '..')
+const output = resolve(root, 'apps/nest-node-probe/dist')
+const source = resolve(root, 'apps/nest-node-probe/correctness/set-immediate.ts')
+const executable = resolve(output, 'set-immediate')
+const options = { cwd: root, encoding: 'utf8', env: { ...process.env, TMPDIR: output } }
+mkdirSync(output, { recursive: true })
+
+execFileSync(process.execPath, [resolve(root, 'scripts/build.mjs'), source, '--out', output, '--exe', executable], {
+  ...options,
+  stdio: 'inherit'
+})
+const expected = spawnSync(process.execPath, [source], { ...options, timeout: 15000 })
+const actual = spawnSync(executable, [], { ...options, timeout: 15000 })
+assert.equal(expected.status, 0, `node status\n${expected.stderr}`)
+assert.equal(actual.status, 0, `compiled status\n${actual.stderr}`)
+const expectedLines = expected.stdout.trim().split('\n')
+const actualLines = actual.stdout.trim().split('\n')
+assert.equal(actualLines.length, expectedLines.length, `line count\n--- node\n${expected.stdout}\n--- compiled\n${actual.stdout}`)
+for (let i = 0; i < expectedLines.length; i++) assert.equal(actualLines[i], expectedLines[i], `line ${i + 1}`)
+assert.ok(expectedLines.includes('immediate queued by a (next turn)') && !expectedLines.includes('unref immediate ran'), 'the oracle covered the phases')
+console.log(`SET_IMMEDIATE_PARITY_OK:${expectedLines.length}`)
diff --git a/tools/node-api/generate-surface.mjs b/tools/node-api/generate-surface.mjs
index e516570..de8154e 100644
--- a/tools/node-api/generate-surface.mjs
+++ b/tools/node-api/generate-surface.mjs
@@ -47,7 +47,7 @@ const internalOverlayExports = new Map(
     'node:process': ['WriteStream'],
     'node:stream': ['duplexToWeb', 'finishedPromise', 'pipelinePromise'],
     'node:stream/promises': ['nodeStreamPromiseFinished', 'nodeStreamPromisePipeline'],
-    'node:timers': ['Timeout']
+    'node:timers': ['Timeout', 'Immediate']
   }).map(([moduleName, names]) => [moduleName, new Set(names)])
 )
 const overlayPublicExportTargets = new Map([