diff --git a/src/corelib/itemmodels/qabstractitemmodel.cpp b/src/corelib/itemmodels/qabstractitemmodel.cpp
index 00526dd5bf1..604b4a19c69 100644
--- a/src/corelib/itemmodels/qabstractitemmodel.cpp
+++ b/src/corelib/itemmodels/qabstractitemmodel.cpp
@@ -2660,6 +2660,7 @@ QHash<int,QByteArray> QAbstractItemModel::roleNames() const
 {
     // if the return value ever becomes dependent on *this, also change the following overrides:
     // - QFileSystemModel
+    // - QConcatenateTablesProxyModel
     return QAbstractItemModelPrivate::defaultRoleNames();
 }
 
diff --git a/src/corelib/itemmodels/qconcatenatetablesproxymodel.cpp b/src/corelib/itemmodels/qconcatenatetablesproxymodel.cpp
index db1e041137f..a328a229f96 100644
--- a/src/corelib/itemmodels/qconcatenatetablesproxymodel.cpp
+++ b/src/corelib/itemmodels/qconcatenatetablesproxymodel.cpp
@@ -61,6 +61,7 @@ public:
         ConnArray connections;
     };
     QList<ModelInfo> m_models;
+    mutable QHash<int, QByteArray> m_roleNames;
 
     QList<ModelInfo>::const_iterator findSourceModel(const QAbstractItemModel *m) const
     {
@@ -77,6 +78,9 @@ public:
     // for columns{AboutToBe,}{Inserted,Removed}
     int m_newColumnCount;
 
+    mutable uint m_roleNamesDirty : 1;
+    uint m_reserved : 31;
+
     // for layoutAboutToBeChanged/layoutChanged
     QList<QPersistentModelIndex> layoutChangePersistentIndexes;
     QList<QModelIndex> layoutChangeProxyIndexes;
@@ -85,7 +89,9 @@ public:
 QConcatenateTablesProxyModelPrivate::QConcatenateTablesProxyModelPrivate()
     : m_rowCount(0),
       m_columnCount(0),
-      m_newColumnCount(0)
+      m_newColumnCount(0),
+      m_roleNamesDirty(true),
+      m_reserved(0)
 {
 }
 
@@ -507,6 +513,12 @@ void QConcatenateTablesProxyModel::addSourceModel(QAbstractItemModel *sourceMode
         QObjectPrivate::connect(sourceModel, &QAbstractItemModel::modelReset,
                                 d, &QConcatenateTablesProxyModelPrivate::slotModelReset),
     });
+    if (!d->m_roleNamesDirty) {
+        // do update immediately, since append() is a simple update:
+        const auto newRoleNames = sourceModel->roleNames();
+        for (const auto &[k, v] : newRoleNames.asKeyValueRange())
+            d->m_roleNames.insert_or_assign(k, v);
+    }
     if (newRows > 0)
         endInsertRows();
 
@@ -533,6 +545,7 @@ void QConcatenateTablesProxyModel::removeSourceModel(QAbstractItemModel *sourceM
     if (rowsRemoved > 0)
         beginRemoveRows(QModelIndex(), rowsPrior, rowsPrior + rowsRemoved - 1);
     d->m_models.erase(it);
+    d->m_roleNamesDirty = true;
     d->m_rowCount -= rowsRemoved;
     if (rowsRemoved > 0)
         endRemoveRows();
@@ -551,10 +564,13 @@ void QConcatenateTablesProxyModel::removeSourceModel(QAbstractItemModel *sourceM
 QHash<int, QByteArray> QConcatenateTablesProxyModel::roleNames() const
 {
     Q_D(const QConcatenateTablesProxyModel);
-    QHash<int, QByteArray> ret = QAbstractItemModel::roleNames();
-    for (const auto &[model, _] : d->m_models)
-        ret.insert(model->roleNames());
-    return ret;
+    if (d->m_roleNamesDirty) {
+        d->m_roleNames = QAbstractItemModelPrivate::defaultRoleNames();
+        for (const auto &[model, _] : d->m_models)
+            d->m_roleNames.insert(model->roleNames());
+        d->m_roleNamesDirty = false;
+    }
+    return d->m_roleNames;
 }
 
 void QConcatenateTablesProxyModelPrivate::slotRowsAboutToBeInserted(const QModelIndex &parent,