diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibility.mm b/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
index 69ec52afe7..c5e40a4087 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibility.mm
@@ -136,6 +136,7 @@ static void populateRoleMap()
     roleMap[QAccessible::Note] = NSAccessibilityGroupRole;
     roleMap[QAccessible::ComplementaryContent] = NSAccessibilityGroupRole;
     roleMap[QAccessible::Graphic] = NSAccessibilityImageRole;
+    roleMap[QAccessible::Tree] = NSAccessibilityOutlineRole;
 }
 
 /*
diff --git a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
index d63c0401fd..27fd32f91f 100644
--- a/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
+++ b/src/plugins/platforms/cocoa/qcocoaaccessibilityelement.mm
@@ -292,7 +292,9 @@ static void convertLineOffset(QAccessibleTextInterface *text, int *line, int *of
         QAccessibleTableInterface *table = iface->tableInterface();
         Q_ASSERT(table);
         QAccessibleInterface *cell = table->cellAt(m_rowIndex, m_columnIndex);
-        Q_ASSERT(cell && cell->isValid());
+        if (!cell)
+            return nullptr;
+        Q_ASSERT(cell->isValid());
         iface = cell;
 
         // no longer a placeholder
diff --git a/src/widgets/itemviews/qtreeview.cpp b/src/widgets/itemviews/qtreeview.cpp
index 2280cdaa2e..d4c5d837a8 100644
--- a/src/widgets/itemviews/qtreeview.cpp
+++ b/src/widgets/itemviews/qtreeview.cpp
@@ -3325,6 +3325,16 @@ void QTreeViewPrivate::layout(int i, bool recursiveExpanding, bool afterIsUninit
         return;
     }
 
+    // QAccessibleTree's rowCount implementation uses viewItems.size(), so
+    // we need to invalidate any cached accessibility data structures if
+    // that value changes during the run of this function.
+    const auto resetModelIfNeeded = qScopeGuard([oldViewItemsSize = viewItems.size(), this, q]{
+        if (oldViewItemsSize != viewItems.size() && QAccessible::isActive()) {
+            QAccessibleTableModelChangeEvent event(q, QAccessibleTableModelChangeEvent::ModelReset);
+            QAccessible::updateAccessibility(&event);
+        }
+    });
+
     int count = 0;
     if (model->hasChildren(parent)) {
         if (model->canFetchMore(parent)) {
diff --git a/tests/auto/other/qaccessibilitymac/tst_qaccessibilitymac.mm b/tests/auto/other/qaccessibilitymac/tst_qaccessibilitymac.mm
index 8dc1460585..730e8f7e96 100644
--- a/tests/auto/other/qaccessibilitymac/tst_qaccessibilitymac.mm
+++ b/tests/auto/other/qaccessibilitymac/tst_qaccessibilitymac.mm
@@ -407,6 +407,7 @@ private Q_SLOTS:
     void notificationsTest();
     void checkBoxTest();
     void tableViewTest();
+    void treeViewTest();
 
 private:
     AccessibleTestWindow *m_window;
@@ -732,5 +733,54 @@ void tst_QAccessibilityMac::tableViewTest()
     }
 }
 
+void tst_QAccessibilityMac::treeViewTest()
+{
+    QTreeWidget *tw = new QTreeWidget;
+    tw->setColumnCount(2);
+    QTreeWidgetItem *root = new QTreeWidgetItem(tw, {"/", "0"});
+    root->setExpanded(false);
+    QTreeWidgetItem *users = new QTreeWidgetItem(root,{ "Users", "1"});
+    (void)new QTreeWidgetItem(root, {"Applications", "2"});
+    QTreeWidgetItem *lastChild = new QTreeWidgetItem(root, {"Libraries", "3"});
+
+    m_window->addWidget(tw);
+    QVERIFY(QTest::qWaitForWindowExposed(m_window));
+    QCoreApplication::processEvents();
+
+    TestAXObject *appObject = [TestAXObject getApplicationAXObject];
+    QVERIFY(appObject);
+
+    NSArray *windowList = [appObject windowList];
+    // one window
+    QVERIFY([windowList count] == 1);
+    AXUIElementRef windowRef = (AXUIElementRef)[windowList objectAtIndex:0];
+    QVERIFY(windowRef != nil);
+    TestAXObject *window = [[TestAXObject alloc] initWithAXUIElementRef:windowRef];
+
+    // children of window
+    AXUIElementRef treeView = [window findDirectChildByRole:kAXOutlineRole];
+    QVERIFY(treeView != nil);
+
+    TestAXObject *tv = [[TestAXObject alloc] initWithAXUIElementRef:treeView];
+
+    // here start actual treeview tests. NSAccessibilityOutline is a specialization
+    // of NSAccessibilityTable, and we represent trees as tables.
+    // Should have 2 columns
+    const unsigned int columnCount = 2;
+    NSArray *columnArray = [tv tableColumns];
+    QCOMPARE([columnArray count], columnCount);
+
+    // should have 1 row for now - as long as the root item is not expanded
+    NSArray *rowArray = [tv tableRows];
+    QCOMPARE(int([rowArray count]), 1);
+
+    root->setExpanded(true);
+    rowArray = [tv tableRows];
+    QCOMPARE(int([rowArray count]), root->childCount() + 1);
+
+    // this should not trigger any assert
+    tw->setCurrentItem(lastChild);
+}
+
 QTEST_MAIN(tst_QAccessibilityMac)
 #include "tst_qaccessibilitymac.moc"