The 30-year-old, who joined from Newcastle United, has been an integral member of Mauricio Pochettino's side since his arrival from St James' Park in 2016.
The seasoned France international, a fan favourite at Tottenham Hotspur Stadium, was a member of the Spurs squad that achieved a top-four finish and reached last season's Champions League final against Liverpool.
Speaking to Tottenham's official website, Sissoko spoke about his pride at being rewarded with fresh terms and that he hopes to help inspire younger talents at the club to greater success over the near future.
“I’m very proud to sign a new deal with the club," he stated. "That means they believe in me and are happy with what I’m doing so I can give my best to the club for a long time.
“Hopefully everyone will be happy with my new contract, and of course my family and friends are very happy and proud because they know at the beginning it was tough for me. But I never gave up, I always believed in myself, I was trying to do my best even in the bad moments.
“I’ve learned a lot as a man and as a footballer. The talents of the players and coaching staff [here] are unbelievable so I’ve learned a lot from them, and as a person as well. We can achieve some good moments all together.
“I try to be [a leader]. I have a lot of experience now I’m 30 years old. It is always important to have something from the experienced players so that is what I’m trying to do. We’re all together in the same boat and if we want to have success together, you have to have the right person beside you.
"We know it will be hard [to top last season] but in football and life, everything is possible. You just have to believe in yourself and anything can happen."
There, in a three-year stint, he was unable to prevent their relegation in 2016, but his skills caught the eye of Spurs who beat off Everton to sign him on a five-year deal.
His efforts for the club won him the Legends' Player of the Season this year, as voted for by former Tottenham footballers, as he helped them to a best-ever finish in Europe, coupled with another strong Premier League campaign.
At international level, Sissoko made his debut for France in 2009 and has gone on to win 55 caps, earning inclusion in both their 2014 World Cup and 2016 European Championship squads, though he missed out on selection for Russia last year.