diff --git a/Lib/unittest/main.py b/Lib/unittest/main.py
--- a/Lib/unittest/main.py
+++ b/Lib/unittest/main.py
@@ -1,7 +1,7 @@
 """Unittest main program"""
 
 import sys
-import optparse
+import argparse
 import os
 
 from . import loader, runner
@@ -145,21 +145,21 @@
             return
 
         parser = self._getOptParser()
-        options, args = parser.parse_args(argv[1:])
+        options = parser.parse_args(argv[1:])
         self._setAttributesFromOptions(options)
 
-        if len(args) == 0 and self.module is None:
+        if len(options.tests) == 0 and self.module is None:
             # this allows "python -m unittest -v" to still work for
             # test discovery. This means -c / -b / -v / -f options will
             # be handled twice, which is harmless but not ideal.
-            self._do_discovery(argv[1:])
+            self._do_discovery(options=options)
             return
 
-        if len(args) == 0 and self.defaultTest is None:
+        if len(options.tests) == 0 and self.defaultTest is None:
             # createTests will load tests from self.module
             self.testNames = None
-        elif len(args) > 0:
-            self.testNames = _convert_names(args)
+        elif len(options.tests) > 0:
+            self.testNames = _convert_names(options.tests)
             if __name__ == '__main__':
                 # to support python -m unittest ...
                 self.module = None
@@ -178,26 +178,27 @@
                                                            self.module)
 
     def _getOptParser(self):
-        import optparse
-        parser = optparse.OptionParser()
+        parser = argparse.ArgumentParser()
         parser.prog = self.progName
-        parser.add_option('-v', '--verbose', dest='verbose', default=False,
-                          help='Verbose output', action='store_true')
-        parser.add_option('-q', '--quiet', dest='quiet', default=False,
-                          help='Quiet output', action='store_true')
+        parser.add_argument('-v', '--verbose', dest='verbose', default=False,
+                            help='Verbose output', action='store_true')
+        parser.add_argument('-q', '--quiet', dest='quiet', default=False,
+                            help='Quiet output', action='store_true')
 
         if self.failfast != False:
-            parser.add_option('-f', '--failfast', dest='failfast', default=False,
-                              help='Stop on first fail or error',
-                              action='store_true')
+            parser.add_argument('-f', '--failfast', dest='failfast', default=False,
+                                help='Stop on first fail or error',
+                                action='store_true')
         if self.catchbreak != False:
-            parser.add_option('-c', '--catch', dest='catchbreak', default=False,
-                              help='Catch ctrl-C and display results so far',
-                              action='store_true')
+            parser.add_argument('-c', '--catch', dest='catchbreak', default=False,
+                                help='Catch ctrl-C and display results so far',
+                                action='store_true')
         if self.buffer != False:
-            parser.add_option('-b', '--buffer', dest='buffer', default=False,
-                              help='Buffer stdout and stderr during tests',
-                              action='store_true')
+            parser.add_argument('-b', '--buffer', dest='buffer', default=False,
+                                help='Buffer stdout and stderr during tests',
+                                action='store_true')
+
+        parser.add_argument('tests', nargs='*')
         return parser
 
     def _setAttributesFromOptions(self, options):
@@ -216,23 +217,25 @@
             self.verbosity = 0
 
     def _addDiscoveryOptions(self, parser):
-        parser.add_option('-s', '--start-directory', dest='start', default='.',
-                          help="Directory to start discovery ('.' default)")
-        parser.add_option('-p', '--pattern', dest='pattern', default='test*.py',
-                          help="Pattern to match tests ('test*.py' default)")
-        parser.add_option('-t', '--top-level-directory', dest='top', default=None,
-                          help='Top level directory of project (defaults to start directory)')
+        parser.add_argument('-s', '--start-directory', dest='start', default='.',
+                            help="Directory to start discovery ('.' default)")
+        parser.add_argument('-p', '--pattern', dest='pattern', default='test*.py',
+                            help="Pattern to match tests ('test*.py' default)")
+        parser.add_argument('-t', '--top-level-directory', dest='top', default=None,
+                            help='Top level directory of project (defaults to start directory)')
 
-    def _do_discovery(self, argv, Loader=None):
+    def _do_discovery(self, argv=(), Loader=None, *, options=None):
         if Loader is None:
             Loader = lambda: self.testLoader
 
-        # handle command line args for test discovery
-        self.progName = '%s discover' % self.progName
-        parser = self._getOptParser()
-        self._addDiscoveryOptions(parser)
+        if options is None:
+            # handle command line args for test discovery
+            self.progName = '%s discover' % self.progName
+            parser = self._getOptParser()
+            self._addDiscoveryOptions(parser)
+            options = parser.parse_args(argv)
 
-        options, args = parser.parse_args(argv)
+        args = options.tests
         if len(args) > 3:
             self.usageExit()
 
diff --git a/Lib/unittest/test/test_discovery.py b/Lib/unittest/test/test_discovery.py
--- a/Lib/unittest/test/test_discovery.py
+++ b/Lib/unittest/test/test_discovery.py
@@ -259,9 +259,10 @@
 
         args = ['something', '-v', '-b', '-v', '-c', '-f']
         self.called = False
-        def do_discovery(argv):
+        def do_discovery(argv=(), options=None):
             self.called = True
-            self.assertEqual(argv, args[1:])
+            self.assertTrue(options.verbose)
+            self.assertTrue(options.failfast)
         program._do_discovery = do_discovery
         program.parseArgs(args)
         self.assertTrue(self.called)