diff --git a/src/gtk/listbox.cpp b/src/gtk/listbox.cpp
index 7407fcf5ed..952b509161 100644
--- a/src/gtk/listbox.cpp
+++ b/src/gtk/listbox.cpp
@@ -460,9 +460,13 @@ int wxListBox::DoInsertOneItem(const wxString& item, unsigned int pos)
 #else
     int entryCol = 0;
 #endif
-    gtk_list_store_insert_with_values(m_liststore, NULL, pos, entryCol, entry, -1);
+    GtkTreeIter iter;
+    gtk_list_store_insert_with_values(m_liststore, &iter, pos, entryCol, entry, -1);
     g_object_unref(entry);
 
+    if (HasFlag(wxLB_SORT))
+        pos = GTKGetIndexFor(iter);
+
     return pos;
 }
 
diff --git a/tests/controls/listboxtest.cpp b/tests/controls/listboxtest.cpp
index 86659270fb..543b3e1245 100644
--- a/tests/controls/listboxtest.cpp
+++ b/tests/controls/listboxtest.cpp
@@ -122,9 +122,10 @@ void ListBoxTestCase::Sort()
     CPPUNIT_ASSERT_EQUAL("aab", m_list->GetString(4));
     CPPUNIT_ASSERT_EQUAL("aba", m_list->GetString(5));
 
-    m_list->Append("a");
+    m_list->Append("a", wxUIntToPtr(1));
 
     CPPUNIT_ASSERT_EQUAL("a", m_list->GetString(0));
+    CPPUNIT_ASSERT_EQUAL(wxUIntToPtr(1), m_list->GetClientData(0));
 #endif
 }