diff --git a/autotests/kfiledialog_unittest.cpp b/autotests/kfiledialog_unittest.cpp
--- a/autotests/kfiledialog_unittest.cpp
+++ b/autotests/kfiledialog_unittest.cpp
@@ -104,11 +104,11 @@
 
         QFETCH(QStringList, mimeTypeFilters);
         dialog.setMimeTypeFilters(mimeTypeFilters);
-        dialog.show();
 
         QFETCH(QString, targetMimeTypeFilter);
         dialog.selectMimeTypeFilter(targetMimeTypeFilter);
 
+        dialog.show();
         QCOMPARE(dialog.selectedMimeTypeFilter(), targetMimeTypeFilter);
     }
 
diff --git a/src/platformtheme/kdeplatformfiledialoghelper.cpp b/src/platformtheme/kdeplatformfiledialoghelper.cpp
--- a/src/platformtheme/kdeplatformfiledialoghelper.cpp
+++ b/src/platformtheme/kdeplatformfiledialoghelper.cpp
@@ -315,9 +315,17 @@
             dialog->m_fileWidget->setFilter(qt2KdeFilter(nameFilters));
         }
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 9, 0)
+        if (!options()->initiallySelectedMimeTypeFilter().isEmpty()) {
+            selectMimeTypeFilter(options()->initiallySelectedMimeTypeFilter());
+        } else if (!options()->initiallySelectedNameFilter().isEmpty()) {
+            selectNameFilter(options()->initiallySelectedNameFilter());
+        }
+#else
         if (!options()->initiallySelectedNameFilter().isEmpty()) {
             selectNameFilter(options()->initiallySelectedNameFilter());
         }
+#endif
 
         // overwrite option
         if (options()->testOption(QFileDialogOptions::FileDialogOption::DontConfirmOverwrite)) {
diff --git a/tests/qfiledialogtest.cpp b/tests/qfiledialogtest.cpp
--- a/tests/qfiledialogtest.cpp
+++ b/tests/qfiledialogtest.cpp
@@ -37,6 +37,7 @@
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("nameFilter")), QStringLiteral("Dialog nameFilter, e. g. 'cppfiles (*.cpp *.h *.hpp)', can be specified multiple times"), QStringLiteral("nameFilter"), QStringLiteral("Everything (*)")));
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("mimeTypeFilter")), QStringLiteral("Dialog mimeTypeFilter, e. g. 'application/json', can be specified multiple times"), QStringLiteral("mimeTypeFilter")));
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("selectNameFilter")), QStringLiteral("Initially selected nameFilter"), QStringLiteral("selectNameFilter")));
+    parser.addOption(QCommandLineOption(QStringList(QStringLiteral("selectMimeTypeFilter")), QStringLiteral("Initially selected mimeTypeFilter"), QStringLiteral("selectMimeTypeFilter")));
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("selectFile")), QStringLiteral("Initially selected file"), QStringLiteral("filename")));
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("selectDirectory")), QStringLiteral("Initially selected directory"), QStringLiteral("dirname")));
     parser.addOption(QCommandLineOption(QStringList(QStringLiteral("modal")), QStringLiteral("Test modal dialog"), QStringLiteral("modality"), QStringLiteral("on")));
@@ -86,8 +87,11 @@
     }
 
     QString selectNameFilter = parser.value(QStringLiteral("selectNameFilter"));
+    QString selectMimeTypeFilter = parser.value(QStringLiteral("selectMimeTypeFilter"));
     if (!selectNameFilter.isEmpty()) {
         dialog.selectNameFilter(selectNameFilter);
+    } else if (!selectMimeTypeFilter.isEmpty()) {
+        dialog.selectMimeTypeFilter(selectMimeTypeFilter);
     }
 
     if (parser.value(QStringLiteral("confirmOverwrite")) == QStringLiteral("off")) {