The 23-year-old centre-back, who has made 30 appearances since joining from Shrewsbury in 2015, will remain at the Amex Stadium until the summer of 2020.
"Connor has made great progress in his first year and earned his new deal," Albion boss Chris Hughton said.
"He thoroughly deserves it and I've no doubt he has a very bright future ahead with us."
Brighton & Hove Albion defender Connor Goldson has signed a new four-year contract with the Championship club.