Los Angeles shot just 34 percent and made 3-of-19 from 3-point range in what was the second contest in an eight-game road trip. The Clippers will not play at home again until Feb. 13.
Gay was obtained as part of a three-team trade earlier in the week and came off the bench in his first game with his new club. He hit 8-of-16 shots from the field while playing 33 minutes.
Toronto allowed the Clippers just 45 points through the first three periods and had a 27-point cushion heading into the fourth quarter.
Amir Johnson and DeMar DeRozan scored 19 points each for the Raptors, who ended a three-game skid.
Los Angeles was led by 17 points from Blake Griffin.