diff --git a/cliff/sphinxext.py b/cliff/sphinxext.py
index 5ec34485..8a9a2e62 100644
--- a/cliff/sphinxext.py
+++ b/cliff/sphinxext.py
@@ -15,6 +15,7 @@
 import argparse
 import fnmatch
 import importlib
+import inspect
 import re
 import sys
 
@@ -242,6 +243,8 @@ class AutoprogramCliffDirective(rst.Directive):
             cliff_app_class = getattr(sys.modules[mod_str], class_str)
         except AttributeError:
             return
+        if not inspect.isclass(cliff_app_class):
+            return
         if not issubclass(cliff_app_class, app.App):
             return
         app_arguments = self.options.get('arguments', '').split()