The former England goalkeeper has put pen to paper on a fresh one-year deal that will keep him at Spurs until the summer of 2025.
Forster was initially signed by Tottenham on a free transfer in the summer of 2022 following his exit from Southampton, penning a two-year contract.
The 35-year-old has since made 21 appearances across all competitions, serving primarily as the experienced deputy to both former captain Hugo Lloris and new No1 Guglielmo Vicario.
Forster has played just once since the £17.2million summer arrival of Italy international Vicario from Serie A side Empoli, in the Carabao Cup second-round defeat by London rivals Fulham at Craven Cottage back in August.
However, he made 20 senior appearances across all competitions last term as Lloris struggled with injury problems.
Forster has been on the bench for all but one of Spurs' 14 Premier League games so far this term, missing the opener with Brentford due to back issues as Brandon Austin stepped up to cover for Vicario instead.
Lloris remains at Spurs but is unlikely to play again until January when he is expected to leave the club, while another goalkeeper, Alfie Whiteman, suffered a serious ankle injury during pre-season.
"From the second I got here I've loved being at the club," Forster told Tottenham's official website. "We've got a fantastic squad, I've loved my time here so far and I'm delighted to extend that.
"It's fantastic working with the new manager. Ange [Postecoglou] has come in and everyone loves him. You can see the atmosphere in the stadium and what we're producing.
"It's great to be a part of that and great to help the team in any way I can."