The new deal will keep the Scotland Under-21 captain at the club until the summer of 2011.
The 21-year-old spent the end of last season on loan at Dundee United.
“I’m very pleased to agree this new contract with the club,” he told the club’s official website.
“I have really enjoyed my time so far at Celtic and have been fortunate to make a number of appearances already in the first team.
“This is now something I want to build on and I’m committed to doing all I can to work hard and ensure that I can feature more and more.”
