Spurs manager Harry Redknapp said: "It's great to have Gareth sign a new contract at the club.
"He is a fantastic player and the type we need to be keeping at Spurs. He's got his whole future ahead and he has everything going for him."
Redknapp added: "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."
Bale, who joined Spurs from Southampton for an initial ?5m in 2007, said: "I am enjoying my football at Tottenham. I want us to keep going forward as a team and hopefully we can achieve big things.
"We have got a great squad that is still young and we are going places. It is great to commit to the club, and hopefully we can achieve what we believe we can with this squad.
"The players want what the fans want, and performing in front of these fans is a special experience.
"I definitely believe we can challenge for a title very soon. That is why I have signed. Every year as a minimum we are aiming to qualify for the Champions League, so we are definitely going in the right direction.
"We have proven in the Champions League this season that we can compete with the best and we are in the last eight now and there is no reason we can't go further this season and in years to come."
Source: BBC Sport
Source: BBC Sport