diff --git a/openmc/universe.py b/openmc/universe.py
index 006a77a54..d36b167a5 100644
--- a/openmc/universe.py
+++ b/openmc/universe.py
@@ -76,7 +76,7 @@ class Universe(object):
             return False
         elif self.name != other.name:
             return False
-        elif dict.__eq__(self.cells, other.cells):
+        elif dict.__ne__(self.cells, other.cells):
             return False
         else:
             return True