Dallas, who finished third in the Western Conference, advanced to the club's first-ever league final after ousting the defending champions Real Salt Lake and the Supporters' Shield winners, the LA Galaxy.
The Rapids, who finished 7th in the Western Conference, crossed over to the Eastern Conference playoff bracket, where they upset the Columbus Crew in the first round then edged the San Jose Earthquakes to earn their second-ever MLS Cup berth. They have not played in the final since 1997, when they lost to D.C. United.
The two sides drew both meetings this year. Things ended 1-1 in at Dick's Sporting Goods Park on July 31, and 2-2 at Pizza Hut Park on October 9.
Dallas and Colorado have met in four series in the playoffs. The Rapids have won each time.