The news will come as a huge sigh of relief for Brighton manager Graham Potter as Chelsea were reported to be considering a move for Dunk.
Bar a short loan spell at Bristol City in 2013, Dunk has spent his entire career at Brighton, where he is now captain.
“Brighton Hove Albion are delighted to announce that captain Lewis Dunk has signed a new five-year contract tying him to the club until the end of the 2024/25 season,” a Brighton statement read.
The 28-year-old made 36 Premier League appearances for Brighton last season, scoring three goals, as the Seagulls finished in 15th position.
Manager Potter told the club's website: "We're absolutely delighted that Lewis has made this long-term commitment to the club. It's fantastic news for everyone: the club, the supporters, the team and myself.
"Since I came to the club he's been a joy to work with and he's a top player. We are very lucky to have him.
"I think his role as captain is one he’s grown into and one he will do better and better for the next few years."
Dunk said: "I'm delighted to have signed a new contract. The aim now is to build on a record Premier League season and help the club continue its recent progress over the next five years."
Dunk won his one and only England cap against the United States two years ago.
