Britton has played for Swansea in the top four divisions of England's football pyramid, initially beginning his time at the club with a loan from West Ham in 2002.
He signed a permanent deal at the Welsh club in 2003 and despite leaving for Sheffield United in June 2010, returned to Swansea later that season.
The 31-year-old has made 469 appearances for Swansea in all competitions and had two years remaining on his deal, but has extended his deal by a further 12 months as Garry Monk's side prepare for another Premier League campaign.
"To stay on at the club for an extra year on top of my current contract is something that I am delighted to do," Britton told Swansea's official website.
"From a personal point of view, the contract talks these days are so easy. It was done within a day or two with no complications.
"I just wanted to get it done and signed and the club were happy to get it sorted quickly too.
"I'm happy the club still feels I'm able to compete and do well at this level at my age.
"It's a big thing for them to have given me this extension and I want to repay the faith the board and manager has shown in me.
"Hopefully I can carry on beyond my 34th birthday, but that's something we'll cross when we come to it."
