The 21-year-old winger has earned a global reputation this season after some outstanding displays in the Champions League, highlighted by his hat-trick against Inter Milan at the San Siro.
Manager Harry Redknapp told the club's website: "It's great to have Gareth sign a new contract at the club.
"He is a fantastic player and the type of player we need to be keeping at Spurs.
"Gareth is now one of the top left sided players in the world, he really is an amazing talent and can only get better. He is a smashing lad as well which is equally as important."
Source: PA
Source: PA