diff --git a/setup.py b/setup.py
index 58852af..9825a6b 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup, find_packages
 
 setup(name='webdiff',
-      version='0.12.0',
+      version='0.12.1',
       description='Two-column web-based git difftool',
       author='Dan Vanderkam',
       author_email='danvdk@gmail.com',
diff --git a/webdiff/app.py b/webdiff/app.py
index 50e8467..809d027 100755
--- a/webdiff/app.py
+++ b/webdiff/app.py
@@ -21,6 +21,8 @@
 import util
 import argparser
 
+VERSION = '0.12.1'
+
 
 def determine_path():
     """Borrowed from wxglade.py"""
@@ -265,7 +267,7 @@ def is_webdiff_from_head():
 def run():
     global DIFF, PORT
     try:
-        parsed_args = argparser.parse(sys.argv[1:])
+        parsed_args = argparser.parse(sys.argv[1:], VERSION)
     except argparser.UsageError as e:
         sys.stderr.write('Error: %s\n\n' % e.message)
         usage_and_die()
diff --git a/webdiff/argparser.py b/webdiff/argparser.py
index e962e02..d1fff45 100644
--- a/webdiff/argparser.py
+++ b/webdiff/argparser.py
@@ -23,9 +23,10 @@ class UsageError(Exception):
 PULL_REQUEST_RE = re.compile(r'http[s]://(?:www.)?github.com\/([^/]+)/([^/]+)/pull/([0-9]+)(?:/.*)?')
 PULL_REQUEST_NUM_RE = re.compile(r'^#([0-9]+)$')
 
-def parse(args):
+def parse(args, version=None):
     """Returns {port, dirs: [], files: [], pr: {owner, repo, number}}."""
     parser = argparse.ArgumentParser(description='Run webdiff.', usage=USAGE)
+    parser.add_argument('--version', action='version', version='webdiff %s' % version)
     parser.add_argument('--port', '-p', type=int, help="Port to run webdiff on.", default=-1)
     parser.add_argument('dirs', type=str, nargs='+',
                         help="Directories to diff, or a github pull request URL.")