Andre Iguodala scored 22 points, Andre Miller had 17 points and a season-high 11 rebounds, and Louis Williams added 17 points to lead the 76ers.
With the game tied at 78, Terry hit a 17-footer to put Dallas ahead for good. Nowitzki followed with a three-point play and Terry converted a solo layup for an 85-78 advantage with 3:55 remaining.
Dallas scored on 10 of its last 11 possessions. Philadelphia couldn't get closer than five the rest of the way in losing for the fifth time in six games.
The 76ers expanded a four-point halftime lead to as many as 12 early in the third quarter.
Terry, who had gone 1-for-9 from the floor in the first half, hit three 3-pointers in the first five minutes of the quarter to get Dallas within 58-51. The Mavericks narrowed the deficit to 66-64 entering the fourth quarter after Terry's 13-point third quarter.
Dallas got off to a 12-6 start with a 10-0 run behind Dampier's six points and six rebounds, but the Mavericks failed to score over the last 5:13 of the opening period.
Philadelphia ended the first quarter with 14 unanswered points for a 20-16 lead. Dallas missed its final seven field goal attempts of the opening quarter.
The 76ers were up at halftime 44-40, paced by 11 points each from Miller and Williams.
Notes: Dallas also had 40 first-half points against Minnesota, matching a season-low for a first half. ... F Elton Brand, the Sixers' top scorer and rebounder, missed his seventh straight game due to a dislocated right shoulder. Brand isn't expected back until mid-January. ... Dallas G Jose Juan Berea (strained left shoulder) was questionable for the game but came off the bench in the first quarter. ... Nowitzki, Howard and Terry combined to miss 17 of their first 22 field goal attempts.
