Dawson joined Spurs from Nottingham Forest in January 2005.
He said: “It’s really great that the club has looked to reward me with a new contract.
“I still had four years left so this represents a further commitment on both my and the club’s behalf.”
Boss Martin Jol added: “I am delighted that Michael has signed a further extension to his contract.
“He is exactly the kind of player that will be part of a bright future for our club.
“I’ve said it before and maybe there are other contenders as well, but he is my player of the season.
“I had a problem in the centre with Anthony Gardner and Ledley King being out, but Michael is always there and I think everybody recognises the honesty in his game.”