Bosh, in his seventh NBA season, scored 44 points to go with 12 rebounds for the Raptors.
The Bucks, however, hit 10 3-point shots and turned the ball over just seven times. Carlos Delfino chipped in 22 points for the Bucks, who returned home after a 1-5 road trip.
Bosh made 15-of-26 attempts from the field and 14-of-15 from the line. Jose Calderon contributed 16 points off the bench for the Raptors.