The Chicago Bears have now won all six games in which they have played Buffalo.
The Bears are 9-0 against the Bills, with the only loss coming in Week 2.
It was a much-needed win for the Bears, who have played their first three games against the Buffalo Bills in their career and have yet to lose to Buffalo since joining the NFL.
The Bills, meanwhile, lost for the first time since Week 3 and were eliminated from playoff contention.
Buffalo is 6-2 all-time against the Bears.