diff --git a/Lib/gettext.py b/Lib/gettext.py
index 4c957c0..f9392d8 100644
--- a/Lib/gettext.py
+++ b/Lib/gettext.py
@@ -419,7 +419,7 @@
     # once.
     result = None
     for mofile in mofiles:
-        key = os.path.abspath(mofile)
+        key = (class_, os.path.abspath(mofile))
         t = _translations.get(key)
         if t is None:
             with open(mofile, 'rb') as fp: