It was the second shutout of the season in the NFL, the other one coming Oct. 31 when Green Bay blanked the New York Jets 9-0.
Miami's roster is riddled with injuries, but the most high-profile ones have come to quarterbacks Chad Pennington and Chad Henne. That left Tyler Thigpen -- a four-year veteran out of Coastal Carolina who was obtained in a trade with Kansas City last season -- as the starter against the talented Chicago defense.
Thigpen completed 17-of-29 passes for 187 yards with one interception. He was sacked six times.
Chicago managed only 268 total yards, but drove to field goals of 46, 24 and 50 yards by Robbie Gould to take a 9-0 lead early in the second half. Forte then finished off a 13-play, 60-yard march with a 2-yard run with 1:57 to go in the third.
The Bears improved to 7-3 and took a half-game lead in the NFC North over Green Bay, pending the Packers' meeting with Minnesota Sunday. Miami is 5-5, dropping 2 1/2 games behind New England and the Jets in the AFC East.
Chicago's Jay Cutler was 16-of-25 for 156 yards with an interception. Forte gained 97 yards on 25 carries.