The result ended the Mavericks' hopes of reaching the Western Conference play-in tournament.
Chicago, which had already clinched an Eastern Conference play-in spot, played without leading scorers DeMar DeRozan and Zach LaVine as well as Patrick Beverley.
Orlando, which was in contention for a play-in spot over the past month following a 5-20 start, played its second game since being eliminated Tuesday.
Grizzlies 137, Bucks 114Jaren Jackson Jr. scored 36 points to lead seven Memphis players in double figures as the Grizzlies clinched the No.
Pascal Siakam scored 19 points, Precious Achiuwa added 16 points, and Fred VanVleet had 12 points and eight assists.