The Pacers improved to 5-0 for the first time in their NBA history and remained the only team in the league without a loss.
Chicago had a two-point lead with eight minutes to play, but Indiana finished the contest on a 32-13 run. Stephenson hit two 3-pointers during that stretch and scored 12 of his 15 points.
Paul George led Indiana with 21 while David West had 17 points and 13 rebounds.
Derek Rose and Luol Deng had 17 each for the Bulls, who fell to 1-3 in the early going. Rose had only two assists for the entire game and both of those came in the final period.
In a battle of two of the best defensive teams in the NBA, Indiana shot 41 percent to 35 for the Bulls.