Spezza, who was acquired by the Stars in July, was due to become an unrestricted free agent at the end of the season but he has penned a four-year contract extension believed to be worth $30million.
The 31-year-old Canadian, whose contract will see him through to the 2018-19 campaign, has scored four goals and dished off 14 assists in 20 games for the Stars this season.
"Jason is a world-class player and his commitment to the organization is a reflection of what we are building in Dallas," Stars general manager Jim Nill said in a statement.
"The professionalism and production he brings to our group is key for our success moving forward and we value the leadership he brings to our team."
The Stars are second-bottom in the Western Conference Central division, with seven wins in 20 games.