diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
index 81b8527f0243..8bf8cef52aad 100644
--- a/lib/matplotlib/widgets.py
+++ b/lib/matplotlib/widgets.py
@@ -928,10 +928,11 @@ def on_submit(self, func):
 
     def disconnect(self, cid):
         """remove the observer with connection id *cid*"""
-        try:
-            del self.observers[cid]
-        except KeyError:
-            pass
+        for reg in (self.change_observers, self.submit_observers):
+            try:
+                del reg[cid]
+            except KeyError:
+                pass
 
 
 class RadioButtons(AxesWidget):