diff --git a/src/corelib/thread/qreadwritelock.cpp b/src/corelib/thread/qreadwritelock.cpp
index 14654986a0..c8463de402 100644
--- a/src/corelib/thread/qreadwritelock.cpp
+++ b/src/corelib/thread/qreadwritelock.cpp
@@ -477,7 +477,7 @@ bool QReadWriteLockPrivate::lockForRead(int timeout)
             if (elapsed > timeout)
                 return false;
             waitingReaders++;
-            readerCond.wait(&mutex, timeout - elapsed);
+            readerCond.wait(&mutex, QDeadlineTimer(timeout - elapsed));
         } else {
             waitingReaders++;
             readerCond.wait(&mutex);
@@ -511,7 +511,7 @@ bool QReadWriteLockPrivate::lockForWrite(int timeout)
                 return false;
             }
             waitingWriters++;
-            writerCond.wait(&mutex, timeout - elapsed);
+            writerCond.wait(&mutex, QDeadlineTimer(timeout - elapsed));
         } else {
             waitingWriters++;
             writerCond.wait(&mutex);
diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index cb3c0d6bb1..b19922753a 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -765,7 +765,7 @@ bool QThread::wait(unsigned long time)
         return true;
 
     while (d->running) {
-        if (!d->thread_done.wait(locker.mutex(), time))
+        if (!d->thread_done.wait(locker.mutex(), QDeadlineTimer(time)))
             return false;
     }
     return true;
diff --git a/src/corelib/thread/qthreadpool.cpp b/src/corelib/thread/qthreadpool.cpp
index 4d2389f699..5f23a78c8a 100644
--- a/src/corelib/thread/qthreadpool.cpp
+++ b/src/corelib/thread/qthreadpool.cpp
@@ -136,7 +136,7 @@ void QThreadPoolThread::run()
             manager->waitingThreads.enqueue(this);
             registerThreadInactive();
             // wait for work, exiting after the expiry timeout is reached
-            runnableReady.wait(locker.mutex(), manager->expiryTimeout);
+            runnableReady.wait(locker.mutex(), QDeadlineTimer(manager->expiryTimeout));
             ++manager->activeThreads;
             if (manager->waitingThreads.removeOne(this))
                 expired = true;
diff --git a/src/corelib/thread/qwaitcondition.h b/src/corelib/thread/qwaitcondition.h
index 11520e4cfe..86e2141f84 100644
--- a/src/corelib/thread/qwaitcondition.h
+++ b/src/corelib/thread/qwaitcondition.h
@@ -40,15 +40,12 @@
 #ifndef QWAITCONDITION_H
 #define QWAITCONDITION_H
 
-#include <QtCore/qglobal.h>
-
-#include <limits.h>
+#include <QDeadlineTimer>
 
 QT_BEGIN_NAMESPACE
 
 #if QT_CONFIG(thread)
 
-class QDeadlineTimer;
 class QWaitConditionPrivate;
 class QMutex;
 class QReadWriteLock;
@@ -59,11 +56,16 @@ public:
     QWaitCondition();
     ~QWaitCondition();
 
-    // ### Qt 6: remove unsigned long overloads
-    bool wait(QMutex *lockedMutex, unsigned long time = ULONG_MAX);
-    bool wait(QMutex *lockedMutex, QDeadlineTimer deadline);
-    bool wait(QReadWriteLock *lockedReadWriteLock, unsigned long time = ULONG_MAX);
-    bool wait(QReadWriteLock *lockedReadWriteLock, QDeadlineTimer deadline);
+    bool wait(QMutex *lockedMutex,
+              QDeadlineTimer deadline = QDeadlineTimer(QDeadlineTimer::Forever));
+    bool wait(QReadWriteLock *lockedReadWriteLock,
+              QDeadlineTimer deadline = QDeadlineTimer(QDeadlineTimer::Forever));
+#if QT_DEPRECATED_SINCE(5, 15)
+    QT_DEPRECATED_VERSION_X_5_15("Use wait(QMutex *lockedMutex, QDeadlineTimer deadline) instead")
+    bool wait(QMutex *lockedMutex, unsigned long time);
+    QT_DEPRECATED_VERSION_X_5_15("Use wait(QReadWriteLock *lockedReadWriteLock, QDeadlineTimer deadline) instead")
+    bool wait(QReadWriteLock *lockedReadWriteLock, unsigned long time);
+#endif
 
     void wakeOne();
     void wakeAll();
diff --git a/src/corelib/thread/qwaitcondition.qdoc b/src/corelib/thread/qwaitcondition.qdoc
index eebc28f059..9da6f6f25c 100644
--- a/src/corelib/thread/qwaitcondition.qdoc
+++ b/src/corelib/thread/qwaitcondition.qdoc
@@ -119,10 +119,22 @@
     \sa wakeOne()
 */
 
+#if QT_DEPRECATED_SINCE(5, 15)
 /*!
     \fn bool QWaitCondition::wait(QMutex *lockedMutex, unsigned long time)
+    \obsolete use wait(QMutex *lockedMutex, QDeadlineTimer deadline) instead
+*/
+/*!
+    \fn bool QWaitCondition::wait(QReadWriteLock *lockedReadWriteLock, unsigned long time)
+    \obsolete use wait(QReadWriteLock *lockedReadWriteLock, QDeadlineTimer deadline) instead
+*/
+#endif
 
-    Releases the \a lockedMutex and waits on the wait condition.  The
+/*!
+    \fn bool QWaitCondition::wait(QMutex *lockedMutex, QDeadlineTimer deadline)
+    \since 5.12
+
+    Releases the \a lockedMutex and waits on the wait condition. The
     \a lockedMutex must be initially locked by the calling thread. If \a
     lockedMutex is not in a locked state, the behavior is undefined. If
     \a lockedMutex is a recursive mutex, this function
@@ -132,10 +144,10 @@
     \list
     \li Another thread signals it using wakeOne() or wakeAll(). This
        function will return true in this case.
-    \li \a time milliseconds has elapsed. If \a time is \c ULONG_MAX
-       (the default), then the wait will never timeout (the event
-       must be signalled). This function will return false if the
-       wait timed out.
+    \li the deadline given by \a deadline is reached. If \a deadline is
+       \c QDeadlineTimer::Forever (the default), then the wait will never
+       timeout (the event must be signalled). This function will return
+       false if the wait timed out.
     \endlist
 
     The \a lockedMutex will be returned to the same locked state. This
@@ -146,8 +158,8 @@
 */
 
 /*!
-    \fn bool QWaitCondition::wait(QReadWriteLock *lockedReadWriteLock, unsigned long time)
-    \since 4.4
+    \fn bool QWaitCondition::wait(QReadWriteLock *lockedReadWriteLock, QDeadlineTimer deadline)
+    \since 5.12
 
     Releases the \a lockedReadWriteLock and waits on the wait
     condition.  The \a lockedReadWriteLock must be initially locked by the
@@ -160,10 +172,10 @@
     \list
     \li Another thread signals it using wakeOne() or wakeAll(). This
        function will return true in this case.
-    \li \a time milliseconds has elapsed. If \a time is \c ULONG_MAX
-       (the default), then the wait will never timeout (the event
-       must be signalled). This function will return false if the
-       wait timed out.
+    \li the deadline given by \a deadline is reached. If \a deadline is
+       \c QDeadlineTimer::Forever (the default), then the wait will never
+       timeout (the event must be signalled). This function will return
+       false if the wait timed out.
     \endlist
 
     The \a lockedReadWriteLock will be returned to the same locked
diff --git a/src/corelib/thread/qwaitcondition_unix.cpp b/src/corelib/thread/qwaitcondition_unix.cpp
index dd7475cec5..a8dfb9999c 100644
--- a/src/corelib/thread/qwaitcondition_unix.cpp
+++ b/src/corelib/thread/qwaitcondition_unix.cpp
@@ -202,12 +202,14 @@ void QWaitCondition::wakeAll()
     report_error(pthread_mutex_unlock(&d->mutex), "QWaitCondition::wakeAll()", "mutex unlock");
 }
 
+#if QT_DEPRECATED_SINCE(5, 15)
 bool QWaitCondition::wait(QMutex *mutex, unsigned long time)
 {
     if (time == std::numeric_limits<unsigned long>::max())
         return wait(mutex, QDeadlineTimer(QDeadlineTimer::Forever));
     return wait(mutex, QDeadlineTimer(time));
 }
+#endif
 
 bool QWaitCondition::wait(QMutex *mutex, QDeadlineTimer deadline)
 {
@@ -229,12 +231,14 @@ bool QWaitCondition::wait(QMutex *mutex, QDeadlineTimer deadline)
     return returnValue;
 }
 
+#if QT_DEPRECATED_SINCE(5, 15)
 bool QWaitCondition::wait(QReadWriteLock *readWriteLock, unsigned long time)
 {
     if (time == std::numeric_limits<unsigned long>::max())
         return wait(readWriteLock, QDeadlineTimer(QDeadlineTimer::Forever));
     return wait(readWriteLock, QDeadlineTimer(time));
 }
+#endif
 
 bool QWaitCondition::wait(QReadWriteLock *readWriteLock, QDeadlineTimer deadline)
 {