diff --git a/python/plugins/processing/ProcessingPlugin.py b/python/plugins/processing/ProcessingPlugin.py
index 9c2cd1b8bc1..87fe6e96af6 100644
--- a/python/plugins/processing/ProcessingPlugin.py
+++ b/python/plugins/processing/ProcessingPlugin.py
@@ -253,6 +253,7 @@ class ProcessingPlugin:
         self.resultsDock.setVisible(False)
         self.iface.removeDockWidget(self.resultsDock)
 
+        self.toolbox.deleteLater()
         self.menu.deleteLater()
 
         # delete temporary output files