Marsh is coming off an effective 2012 season. He had 50 defensive tackles and three interceptions while appearing in all 18 of B.C.'s regular-season games.
Marsh is entering his 10th season with the Lions and it the team's all-time leader in total tackles with 484.
The two-time Grey Cup champion and three-time West Division all-star has recorded at least 50 tackles in each of his past five seasons to go along with 26 career interceptions.
He was entering the option year of his previous contract.
"Few players have enjoyed the type of consistent productivity that Dante has over the past decade," Lions head coach Mike Benevides said in a statement. "We're blessed with a veteran secondary made up of individuals who take enormous pride in their craft and Dante's work ethic has been his calling card since day one."