diff --git a/src/corelib/kernel/qcoreapplication.cpp b/src/corelib/kernel/qcoreapplication.cpp
index 148b60d4abc..d5c5e33cc97 100644
--- a/src/corelib/kernel/qcoreapplication.cpp
+++ b/src/corelib/kernel/qcoreapplication.cpp
@@ -368,14 +368,16 @@ Q_CONSTINIT uint QCoreApplicationPrivate::attribs =
     (1 << Qt::AA_SynthesizeMouseForUnhandledTouchEvents) |
     (1 << Qt::AA_SynthesizeMouseForUnhandledTabletEvents);
 
-struct QCoreApplicationData {
+struct QCoreApplicationData
+{
     QCoreApplicationData() noexcept {
         applicationNameSet = false;
         applicationVersionSet = false;
     }
     ~QCoreApplicationData() {
-#ifndef QT_NO_QOBJECT
+#if !defined(QT_NO_QOBJECT) && defined(Q_OS_WIN)
         // cleanup the QAdoptedThread created for the main() thread
+        // (for Unix systems, see qthread_unix.cpp:set_thread_data())
         if (auto *t = QCoreApplicationPrivate::theMainThread.loadAcquire()) {
             QThreadData *data = QThreadData::get2(t);
             data->deref(); // deletes the data and the adopted thread
diff --git a/src/corelib/thread/qthread_unix.cpp b/src/corelib/thread/qthread_unix.cpp
index 14c6490c1e7..36112afd4df 100644
--- a/src/corelib/thread/qthread_unix.cpp
+++ b/src/corelib/thread/qthread_unix.cpp
@@ -140,12 +140,20 @@ static QThreadData *get_thread_data()
     return currentThreadData;
 }
 
+#if QT_CONFIG(broken_threadlocal_dtors)
+// The destructors registered with pthread_key_create() below are NOT run from
+// exit(), so we must also use atexit().
+static void destroy_main_thread_data()
+{
+    if (QThreadData *d = get_thread_data())
+        destroy_current_thread_data(d);
+}
+Q_DESTRUCTOR_FUNCTION(destroy_main_thread_data)
+#endif
+
 static void set_thread_data(QThreadData *data)
 {
-    // Only activate the late cleanup for auxiliary threads. We can't use
-    // QThread::isMainThread() here because theMainThreadId will not have been
-    // set yet.
-    if (data && QCoreApplicationPrivate::theMainThreadId.loadAcquire()) {
+    if (data) {
         if constexpr (QT_CONFIG(broken_threadlocal_dtors)) {
             static pthread_key_t tls_key;
             struct TlsKey {
@@ -418,7 +426,6 @@ void QThreadPrivate::cleanup()
         d->interruptionRequested.store(false, std::memory_order_relaxed);
 
         d->isInFinish = false;
-        d->data->threadId.storeRelaxed(nullptr);
 
         d->thread_done.wakeAll();
     });
@@ -828,14 +835,14 @@ bool QThread::wait(QDeadlineTimer deadline)
     Q_D(QThread);
     QMutexLocker locker(&d->mutex);
 
+    if (d->finished || !d->running)
+        return true;
+
     if (isCurrentThread()) {
         qWarning("QThread::wait: Thread tried to wait on itself");
         return false;
     }
 
-    if (d->finished || !d->running)
-        return true;
-
     return d->wait(locker, deadline);
 }
 
@@ -848,7 +855,6 @@ bool QThreadPrivate::wait(QMutexLocker<QMutex> &locker, QDeadlineTimer deadline)
         if (!d->thread_done.wait(locker.mutex(), deadline))
             return false;
     }
-    Q_ASSERT(d->data->threadId.loadRelaxed() == nullptr);
 
     return true;
 }
diff --git a/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp b/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
index 5dc445d44f2..a031e6a54d0 100644
--- a/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
+++ b/tests/auto/corelib/kernel/qcoreapplication/tst_qcoreapplication.cpp
@@ -1065,9 +1065,22 @@ static void createQObjectOnDestruction()
     // QThread) after the last QObject has been destroyed (especially after
     // QCoreApplication has).
 
-#if !defined(QT_QGUIAPPLICATIONTEST) && !defined(Q_OS_WIN) && !defined(Q_OS_VXWORKS)
-    // QCoreApplicationData's global static destructor has run and cleaned up
-    // the QAdoptedThread.
+#if defined(QT_QGUIAPPLICATIONTEST)
+    // If we've linked to QtGui, we make no representations about there being
+    // global static (not Q_GLOBAL_STATIC) variables that are QObject.
+#elif QT_CONFIG(broken_threadlocal_dtors)
+    // With broken thread-local destructors, we cannot guarantee the ordering
+    // between thread_local destructors and static-lifetime destructors (hence
+    // why they're broken).
+    //
+    // On Unix systems, we use a Q_DESTRUCTOR_FUNCTION in qthread_unix.cpp to
+    // work around the issue, but that means it cannot have run yet.
+    //
+    // This variable is set on Windows too, even though the nature of the
+    // problem is different.
+#else
+    // The thread_local destructor in qthread_unix.cpp has run so the
+    // QAdoptedThread must have been cleaned up.
     if (theMainThreadIsSet())
         qFatal("theMainThreadIsSet() returned true; some QObject must have leaked");
 #endif