Delon Wright finished with 18 points and a career-best 13 assists for the Grizzlies. Jonas Valanciunas added 18 points and 14 rebounds.
All five starters finished in double figures as the Grizzlies ended a two-game slide.
Paul George led the Thunder with 30 points and 12 rebounds, while Dennis Schroder added 25 points on 9-of-14 shooting. Russell Westbrook finished with 16 points and seven assists, but was just 6 of 20 from the field and missed five of his six 3-point attempts.
Oklahoma City lost for the fifth time in six games.
The Grizzlies, who have struggled at times in the third quarter, stretched their lead to 18 with a 19-7 rally to open the second half. With the lead at 73-55, Thunder coach Billy Donovan called timeout.
At that point, Westbrook was 2 of 13.
He would start taking over the Thunder offence, getting to the basket and making his next four shots. That cut into the Memphis lead before the Grizzlies held an 86-78 advantage heading into the fourth.
Memphis pushed it to 103-90 after Dorsey connected on a 3-pointer with 4:42 left. The Thunder never got closer than seven down the stretch.
Thunder: This was the second game of a two-game road trip, the last multiple-game stint away from home for Oklahoma City this season. .The loss ended a nine-game winning streak for Oklahoma City over Memphis. . C Steven Adams was limited to two points, making only one of his seven shots.
Grizzlies: Starting PG Mike Conley (left thigh soreness) and reserve C Joakim Noah (right knee soreness) sat out. . Hit their first seven shots of the game. . Had not defeated the Thunder since Dec. 29, 2016. . Caboclo’s previous career high was 16 points on Feb. 7 at Oklahoma City.
Thunder: Host the Indiana Pacers on Wednesday.
Grizzlies: Host the Golden State Warriors on Wednesday.