The experienced and popular prop becomes the 10th player this summer to put pen to paper on a new deal to remain at Rodney Parade.
Harris, 34,moved to Dragons in 2014 and has clocked up over a century of appearances since his regional debut against Harlequins.
The South African – who qualified for Wales through residency in 2017 – previously played for Super Rugby side the Stormers and represented Western Province in the Currie Cup.
“I’m happy to get the contract sorted and out of the way to concentrate on rugby now,” said Harris.
“I’m very excited to be back in training in the team environment for a sixth season with the Dragons having had a few weeks away from rugby.
“There is a lot of talent at the Dragons and I’m excited to be part of the squad and to contribute in leading this team on the road to victory.
“I believe we’ll be able to turn this ship around and give the Rodney faithful something to cheer about.”
Harris, who can operate on both sides of the scrum, made his 100th appearance for the region last season when he lined up against ASM Clermont Auvergne in the European Challenge Cup.
Dragons forwards Coach Ceri Jones said: “Brok has been a fantastic servant for Dragons over the last five seasons and become a vital component in our pack.
“He continues to perform at the very highest level and have a huge impact both on and off the field with his leadership and vast experience.
“It is a real boost Brok has signed new terms and we look forward to seeing him in action again next season.”
Brok joins Lewis Evans, Matthew Screech, Lloyd Fairbrother, Tavis Knoyle, Arwel Robson, Adam Warren, Connor Edwards, Jared Rosser and Ashton Hewitt in agreeing new terms with the Dragons.
Dean Ryan’s side have also completed the acquisition of fly-half Sam Davies and prop Jack Cosgrove for next season.
