diff --git a/Lib/getopt.py b/Lib/getopt.py
index 66f4827..251d89c 100644
--- a/Lib/getopt.py
+++ b/Lib/getopt.py
@@ -155,7 +155,7 @@
             if not args:
                 raise GetoptError('option --%s requires argument' % opt, opt)
             optarg, args = args[0], args[1:]
-    elif optarg:
+    elif optarg is not None:
         raise GetoptError('option --%s must not have an argument' % opt, opt)
     opts.append(('--' + opt, optarg or ''))
     return opts, args