Alli was roped in by the Spurs last summer from MK Dons. The 20-year-old English star was revelation in his debut season as Tottenham finished 3rd in the league.
Totteham Hotspur confirmed the new on Twitter. The Tweet read:
The official club statement read: "We are delighted to announce that Dele Alli has signed a new contract with the Club which will run until 2022."
The youngster was delighted after signing a fresh contract extension with the club. Speaking to the club's official website, he said: "I remember that game at Sunderland, I didn't expect to play as quickly as I did and make an impact in the team.
"It's happened so quickly, starting at Tottenham, playing for England... it's been a crazy year for me and there are so many people I have to thank.
"I'm happy to be at this Club and I can't thank the manager and all the staff enough for everything they've done for me, and the fans, they've been right behind me since I signed.
"Hopefully there are a lot of good times to come."It was a crazy year and it still feels like a dream."
He further added: "I've grown up! Well, I've tried to grow up! I've got great people around me to help keep my feet on the ground and I'll keep working hard on my football and keep trying to improve.
"It's a bit surreal but I'm the same kid as I always have been, nothing has changed for me off the pitch, I'm still the same person and thankfully, like I said before, I've got great support around me.
"The hard work isn't going to stop here. I have to keep working hard and keep fighting for my place in this team.
"I have to keep trying to improve, I can't get carried away, I have to keep trying to make each year better than the last. This will be a tough year to top but hopefully I can do it."
Dele Alli played 46 matches for Tottenham last season scoring 10 goals and provided 11 assists. His impressive stint with the club earned him a call up in the England national team in the Euro 2016.