Dawson, 29, who turned down a move to link up with former boss Harry Redknapp at Queens Park Rangers in January, has become a key member of the squad and a regular starter under Andre Villas-Boas.
The centre-half, who joined Spurs in 2005 from Nottingham Forest as a 21-year-old for a fee of around £3.5million, has made 293 appearances for the club.
He had progressed through the underage ranks at Forest to make his senior debut in 2002 and played 91 times in total before heading to N17.
Dawson made his Tottenham debut in a 2-2 Premier League draw with Liverpool at Anfield in April 2005 and was a member of the squad which secured a first-ever top-four finish in the Premier League in 2009/10.
Spurs would go on to reach the last eight of the UEFA Champions League the following season.