Trailing by six to start the fourth quarter, the Sixers started taking - and making - their shots from behind the arc. They finished 8-of-15, but none was bigger than Miller's 3 that answered a Bucks rally.
Luke Ridnour's 3-pointer cut to it 104-103 with 49 seconds to play, but Miller went right back down the floor and answered with his own 3 to push the lead to 107-103.
After Milwaukee's Richard Jefferson, who finished with 27 points, added a layup, Andre Iguodala made one of two free throws with 17 seconds to play.
Charlie Bell missed an off-balance 3 that would've tied it and Iguodala, who had 20 points, grabbed the rebound and hit two free throws to seal the victory, the Sixers' second on the road in their last seven tries.
Lou Williams scored 12 points and Thaddeus Young 10 for the Sixers. Milwaukee got 26 points from Charlie Villanueva, 20 from Michael Redd and 11 from Ridnour.
Philadelphia, winners of back-to-back games after beating Houston on Tuesday night, took its first lead of the second half during a 7-0 run midway through the fourth that featured the Sixers' speed and quickness.
Marreese Speights made a strong move to the rim for a three-point play, then Miller found Speights cutting down the lane for an easy basket, one of six assists for Miller. On the next possession, Young picked off a pass by Jefferson in stride, finishing with an uncontested layup to put the Sixers ahead 99-96 with 3:48 left.
Milwaukee, in the midst of a three-game homestand, lost for just the second time in nine home games. The Bucks again played without center Andrew Bogut, who missed his third straight game because of back spasms.
Notes: There's no timetable for Bogut's return. Milwaukee is 1-2 in the last three games and 1-5 this season without him. ... Miller finished 10-of-11 from the free-throw line. ... Redd and Villanueva combined for 27 of the Bucks' 34 second-quarter points. ... In the first meeting on Dec. 17, Iguodala scored four points on 2-of-14 shooting, while Redd had six points on 2-of-13 shooting. Both players surpassed those point totals a little more than nine minutes into the first quarter.
