diff --git a/src/corelib/thread/qthreadpool.cpp b/src/corelib/thread/qthreadpool.cpp
index f4dc940cc4b..3a9c0569e7c 100644
--- a/src/corelib/thread/qthreadpool.cpp
+++ b/src/corelib/thread/qthreadpool.cpp
@@ -113,7 +113,12 @@ void QThreadPoolThread::run()
         manager->waitingThreads.enqueue(this);
         registerThreadInactive();
         // wait for work, exiting after the expiry timeout is reached
-        runnableReady.wait(locker.mutex(), QDeadlineTimer(manager->expiryTimeout));
+        QDeadlineTimer deadline;
+        if (manager->expiryTimeout.count() < 0)
+            deadline = QDeadlineTimer::Forever;
+        else
+            deadline.setRemainingTime(manager->expiryTimeout);
+        runnableReady.wait(locker.mutex(), deadline);
         // this thread is about to be deleted, do not work or expire
         if (!manager->allThreads.contains(this)) {
             Q_ASSERT(manager->queue.isEmpty());
diff --git a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
index 2006016d478..6decea9b939 100644
--- a/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
+++ b/tests/auto/corelib/thread/qthreadpool/tst_qthreadpool.cpp
@@ -414,6 +414,21 @@ void tst_QThreadPool::expiryTimeout()
 
     threadPool.setExpiryTimeout(expiryTimeout);
     QCOMPARE(threadPool.expiryTimeout(), expiryTimeout);
+
+    threadPool.waitForDone();
+    // Negative times should be 'forever'
+    threadPool.setExpiryTimeout(-1);
+    QCOMPARE(threadPool.expiryTimeout(), -1);
+
+    threadPool.start(&task);
+    QVERIFY(task.semaphore.tryAcquire(1, 10'000));
+    QCOMPARE(task.runCount.loadRelaxed(), 3);
+    firstThread = task.thread;
+
+    QTest::qWait(100); // Let some time elapse after the task finishes...
+
+    // Since the thread never expires it should still be waiting for a new task:
+    QVERIFY(firstThread->isRunning());
 }
 
 void tst_QThreadPool::expiryTimeoutRace() // QTBUG-3786