The Raptors took a four-point lead after one quarter and then faded while Utah was throwing in 13 of its 23 attempts from 3-point range.
Utah improved to 8-1 at home. Toronto has lost three straight and has just one road victory in 13 tries this season. The Raptors have two stops left on their current five-game road trip.
Millsap scored 20 points, Enes Kanter added 18 and Gordon Hayward came off the bench to produce 17 for the Jazz. Utah's bench outscored Toronto's substitute players 55-33.
Andrea Bargnani had 20 points for the Raptors and DeMar DeRozan scored 17.
It was the second and last meeting between the teams this year, Utah having won the first one 140-133.