March has been one of Brighton's best performers in an impressive 2022/2023 season.
The Seagulls are pushing for a European place and are currently sixth on the Premier League table.
March scored his seventh Premier League goal of the season when Brighton defeated Crystal Palace 1-0 on Wednesday.
The 28-year-old has made 266 appearances since breaking into the Brighton first team at the start of the 2013/2014 season.
Brighton manager Roberto De Zerbi expressed delight with March's decision to pen fresh terms at the AMEX Stadium.
"It's great news. Solly deserves this new contract," said the Italian manager, who replaced Graham Potter in September.
"We are all happy for him and I am happy for him because I want all the great players to stay with me."
March is the third Brighton player to extend his contract in recent weeks after Moises Caicedo and Adam Lallana.
Brighton will player Grimsby in the FA Cup quarterfinals on Sunday.