Holliday equaled his season's best scoring effort with 33 points and handed out 14 assists in a dazzling show that rallied the 76ers from a 17-point halftime deficit.
Philadelphia led only once during the game's first 48 minutes, that coming when the 76ers inched in front 74-73 during the opening moments of the fourth period.
The Raptors took a four-point lead with 8.8 seconds to go in the final quarter on a free throw by Alan Anderson, but Philadelphia got a tip-in with 5.9 seconds remaining from Spencer Hawes and Jose Calderon then turned it over for Toronto.
That gave Holliday a chance to tie the game on a driving layup with a second to play. He then went 4-of-6 during the overtime with one of his field goals being a 3-pointer and he also converted 3-of-4 from the foul line.
All of that brought Philadelphia just its third win in 11 games. Thaddeus Young added 27 points and 14 rebounds for the 76ers.
Anderson and Ed Davis both scored 18 points for the Raptors, who owned a 60-43 lead at intermission.