diff --git a/src/corelib/itemmodels/qstringlistmodel.cpp b/src/corelib/itemmodels/qstringlistmodel.cpp
index 0f7472aa5a..da232cc142 100644
--- a/src/corelib/itemmodels/qstringlistmodel.cpp
+++ b/src/corelib/itemmodels/qstringlistmodel.cpp
@@ -131,7 +131,7 @@ int QStringListModel::rowCount(const QModelIndex &parent) const
 */
 QModelIndex QStringListModel::sibling(int row, int column, const QModelIndex &idx) const
 {
-    if (!idx.isValid() || column != 0 || row >= lst.count())
+    if (!idx.isValid() || column != 0 || row >= lst.count() || row < 0)
         return QModelIndex();
 
     return createIndex(row, 0);