diff -r 74236c8bf064 Lib/argparse.py
--- a/Lib/argparse.py	Tue Aug 26 01:02:28 2014 +0200
+++ b/Lib/argparse.py	Tue Aug 26 14:16:45 2014 +0300
@@ -91,6 +91,7 @@
 import textwrap as _textwrap
 
 from gettext import gettext as _, ngettext
+from zipfile import is_zipfile as _is_zipfile
 
 
 SUPPRESS = '==SUPPRESS=='
@@ -1572,6 +1573,24 @@
         self._group_actions.remove(action)
 
 
+def _prog_name(prog):
+    if prog is not None:
+        return prog
+
+    mod = _sys.modules['__main__']
+    arg0 = _sys.argv[0]
+    if mod.__package__ is None:
+        return _os.path.basename(arg0)
+
+    if _is_zipfile(arg0) or _os.path.isdir(arg0):
+        suffix = arg0
+    else:
+        suffix = '-m %s' % mod.__package__
+
+    py = _os.path.basename(_sys.executable)
+    return '%s %s' % (py, suffix)
+
+
 class ArgumentParser(_AttributeHolder, _ActionsContainer):
     """Object for parsing command line strings into Python objects.
 
@@ -1609,11 +1628,7 @@
                   argument_default=argument_default,
                   conflict_handler=conflict_handler)
 
-        # default setting for prog
-        if prog is None:
-            prog = _os.path.basename(_sys.argv[0])
-
-        self.prog = prog
+        self.prog = _prog_name(prog)
         self.usage = usage
         self.epilog = epilog
         self.formatter_class = formatter_class
diff -r 74236c8bf064 Lib/test/test_argparse.py
--- a/Lib/test/test_argparse.py	Tue Aug 26 01:02:28 2014 +0200
+++ b/Lib/test/test_argparse.py	Tue Aug 26 14:16:45 2014 +0300
@@ -15,9 +15,14 @@
 
 from test import support
 from unittest import mock
+
+py_exe = os.path.basename(sys.executable)
+
+
 class StdIOBuffer(StringIO):
     pass
 
+
 class TestCase(unittest.TestCase):
 
     def setUp(self):
@@ -2223,7 +2228,7 @@
         parents = [self.abcd_parent, self.wxyz_parent]
         parser = ErrorRaisingArgumentParser(parents=parents)
         parser_help = parser.format_help()
-        progname = self.main_program
+        progname = '{} -m test'.format(py_exe)
         self.assertEqual(parser_help, textwrap.dedent('''\
             usage: {}{}[-h] [-b B] [--d D] [--w W] [-y Y] a z
 
@@ -2257,7 +2262,7 @@
             ['-y', 'Y', '-z', 'Z'])
 
         parser_help = parser.format_help()
-        progname = self.main_program
+        progname = '{} -m test'.format(py_exe)
         self.assertEqual(parser_help, textwrap.dedent('''\
             usage: {}{}[-h] [-w W] [-x X] [-y Y | -z Z]