The 26-year-old has enjoyed his best season with the Saints this year, shaking off his label as a fringe player and cementing a first-team role under both former boss Nigel Adkins and current manager Mauricio Pochettino.
Puncheon admitted he was concerned about the development of his contract situation but is relieved to have finally signed a new deal with the club and is now keen to look to the future.
“It feels amazing. It’s obviously been a worry because my contract was up at the end of the season, so it was important for me to get tied down,” Puncheon told the clubs official website.
|5/1||The Saints are 5/1 with Bet365 to be relegated from the Premier League this season
Southampton are currently three points above the relegation places and take on QPR on Saturday in what will be an important fixture in the race for Premier League survival.
While staying up is his main concern, Puncheon also believes the club has the potential to challenge for European places in the future.
“I want to finish the season strongly and keep growing as a player – and for us to keep growing as a football club," he continued.
“We got to the Premier League in three years, and now the club has a vision of playing European football – and we want to get there as soon as possible.
“I believe that can happen and, more importantly, the football club believes that can happen. They believe I can be a part of it and so do I."
Pochettino reiterated his desire to extend the player contract only last week, and is pleased to see the club tie Puncheon down for a further three years.
“It’s great news that Jason has agreed to sign a new contract with Southampton," he said.
“I was never in any doubt that he would like to remain at Southampton, and I am looking forward to seeing even more from Jason over the next few years.
“He has been very impressive for the club this season and especially so since I arrived, and he is a very important member of our squad."
“He has responded really well to the challenge of the Premier League and is clearly playing some of the best football of his career, so it’s really pleasing that he is staying here."