Furman has made 100 league appearances for Paul Dickov's side after joining on a free transfer from Rangers in 2009 and the npower League One club have exercised an option in the 23-year-old's contract to prolong his stay in the north west.
"When I signed a three-year contract in 2009, there was an option to extend for another year which I am glad the club has offered me," Furman told Oldham's official website. "I am delighted to accept because I have enjoyed my football here and the last three years have flown by.
"In the past three years there has been some great times and some not too great ones. I have seen what the club is trying to do and hopefully we can build on what has been started.
"It is important we keep as many of our good players as possible and add to them because we have the basis of a very good squad."
Latics chairman Simon Corney added: "Dean has been an outstanding player and last season was arguably our best player and would have been so again this time but for injuries. It is exciting to have him back for next season and we hope he can go from strength to strength because Dean, as captain, is an important part of the jigsaw."