diff --git a/realcentroid.py b/realcentroid.py
index 28ebcaa..15ba138 100644
--- a/realcentroid.py
+++ b/realcentroid.py
@@ -24,7 +24,7 @@
 import os.path
 from PyQt5.QtCore import QSettings, QTranslator, qVersion, QCoreApplication, Qt
 from PyQt5.QtGui import QIcon
-from PyQt5.QtWidgets import QAction
+from PyQt5.QtWidgets import QAction, QMessageBox
 
 from qgis.core import QgsVectorFileWriter, QgsWkbTypes, QgsFeature, \
     QgsMessageLog, QgsVectorLayer, QgsProject
diff --git a/realcentroid_dialog.py b/realcentroid_dialog.py
index d59d437..0a28bba 100644
--- a/realcentroid_dialog.py
+++ b/realcentroid_dialog.py
@@ -90,12 +90,12 @@ def browse(self):
     def ok(self):
         """ check widgets """
         if len(self.layerBox.currentText()) == 0:
-            QtGui.QMessageBox.warning(self, "Realcentroid", \
+            QtWidgets.QMessageBox.warning(self, "Realcentroid", \
                 QtGui.QApplication.translate("RealCentroid", \
                 "No polygon layer selected", None))
             return
         if len(self.pointEdit.text()) == 0:
-            QtGui.QMessageBox.warning(self, "Realcentroid", \
+            QtWidgets.QMessageBox.warning(self, "Realcentroid", \
                 QtGui.QApplication.translate("RealCentroid", \
                 "No point layer given", None))
             return