The 23-year-old, who only signed a two-year contract extension last year, has made 48 appearances for the Gunners since joining from Southampton in 2014.
The length of the new deal for Chambers, who has won three England caps, has not been disclosed but is described as “long-term” by the club.
“He played an important role last season and will be part of my plans this season,” said manager Unai Emery.
Former Paris St-Germain and Sevilla manager Emery has taken over from Arsene Wenger this summer as the Gunners’ new boss.
“I want to give my very best to this great club,” said Chambers, who has also won three caps for England.
“Thanks to the new manger for showing faith in me and I’m looking forward to the big season ahead.
“I promise to repay the fans for the support they’ve given me.”
Source: BBC news
