Carlos Arroyo chipped in 15 points while Udonis Haslem contributed 11 points and 11 rebounds for the playoff-bound Heat, who remained tied with Milwaukee for the fifth seed in the Eastern Conference.
Wade's two free throws with 48.3 seconds to go put the Heat ahead 97-95. The Sixers had a chance to tie with 5.6 seconds remaining when Samuel Dalembert attempted a put-back dunk, but he was whistled for interfering with the ball on the rim and the Heat was awarded possession on the turnover.
Arroyo was then fouled and made both free throws with 4 seconds left to ice the game for Miami.
Dalembert led Philadelphia with 19 points, 16 rebounds and four blocks while Andre Iguodala added 16 points.