diff --git a/tools/checkowners.py b/tools/checkowners.py
new file mode 100755
index 0000000..8f450e7
--- /dev/null
+++ b/tools/checkowners.py
@@ -0,0 +1,76 @@
+#!/usr/bin/python
+
+"""Parse and check syntax errors of a given OWNERS file."""
+
+import argparse
+import re
+import sys
+import urllib2
+
+parser = argparse.ArgumentParser(description='Check OWNERS file syntax')
+parser.add_argument('-v', '--verbose', dest='verbose',
+                    action='store_true', default=False,
+                    help='Verbose output to debug')
+parser.add_argument('-c', '--check_address', dest='check_address',
+                    action='store_true', default=False,
+                    help='Check email addresses')
+parser.add_argument(dest='owners', metavar='OWNERS', nargs='+',
+                    help='Path to OWNERS file')
+args = parser.parse_args()
+
+gerrit_server = 'https://android-review.googlesource.com'
+checked_addresses = {}
+
+
+def echo(msg):
+  if args.verbose:
+    print msg
+
+
+def find_address(address):
+  if address not in checked_addresses:
+    request = gerrit_server + '/accounts/?suggest&q=' + address
+    echo('Checking email address: ' + address)
+    result = urllib2.urlopen(request).read()
+    expected = '"email": "' + address + '"'
+    checked_addresses[address] = (result.find(expected) >= 0)
+  return checked_addresses[address]
+
+
+def main():
+  # One regular expression to check all valid lines.
+  noparent = 'set +noparent'
+  email = '([^@ ]+@[^ @]+|\\*)'
+  directive = '(%s|%s)' % (email, noparent)
+  glob = '[a-zA-Z0-9_\\.\\-\\*\\?]+'
+  perfile = 'per-file +' + glob + ' *= *' + directive
+  pats = '(|%s|%s|%s)$' % (noparent, email, perfile)
+  patterns = re.compile(pats)
+
+  # One pattern to capture email address.
+  email_address = '.*(@| |=|^)([^@ =]+@[^ @]+)'
+  address_pattern = re.compile(email_address)
+
+  error = 0
+  for fname in args.owners:
+    echo('Checking file: ' + fname)
+    num = 0
+    for line in open(fname, 'r'):
+      num += 1
+      stripped_line = re.sub('#.*$', '', line).strip()
+      if not patterns.match(stripped_line):
+        error = 1
+        print('%s:%d: ERROR: unknown line [%s]'
+              % (fname, num, line.strip()))
+      elif args.check_address and address_pattern.match(stripped_line):
+        address = address_pattern.match(stripped_line).group(2)
+        if find_address(address):
+          echo('Found email address: ' + address)
+        else:
+          error = 1
+          print('%s:%d: ERROR: unknown email address: %s'
+                % (fname, num, address))
+  sys.exit(error)
+
+if __name__ == '__main__':
+  main()