diff --git a/rest_framework_jwt/compat.py b/rest_framework_jwt/compat.py
index ea3b4640..93e7898d 100644
--- a/rest_framework_jwt/compat.py
+++ b/rest_framework_jwt/compat.py
@@ -22,7 +22,7 @@ def __init__(self, *args, **kwargs):
 def get_username_field():
     try:
         username_field = get_user_model().USERNAME_FIELD
-    except:
+    except AttributeError:
         username_field = 'username'
 
     return username_field