Avery Bradley also scored 25 points for the Celtics, who built a 33-point lead early in the fourth quarter before Cleveland's reserves cut into the margin. Olynyk had a career-high 12 rebounds, and Jeff Green and Brandon Bass each scored 19 points.
Boston snapped a 13-game road losing streak and won for the first time away from home since Feb. 10. The Celtics broke a nine-game losing streak Friday against playoff-bound Charlotte and have won consecutive games for the first time since early March.
Kyrie Irving scored and Dion Waiters each scored 15 points for Cleveland, but neither played in the fourth quarter that began with Boston leading 89-58. Forward Luol Deng missed his second straight game for Cleveland with a sore back.
Boston used a 10-0 run early in the game to take control. Olynyk hit a 3-pointer and a hook shot, while Bradley also had a 3-pointer to give the Celtics a 19-7 lead.
Cleveland was 6 for 24 from the field in the first quarter, but cut the lead to 31-25 early in the second. The Celtics quickly assumed command again and finished the half on a 15-4 run to lead 60-42.
Bradley and Green hit 3-pointers, while Bass added a basket in the first 1:16 of the third quarter that built the lead to 18 and forced Cleveland coach Mike Brown to call a timeout. The margin steadily grew and reached 33 points, 98-65 early in the fourth.
The Cavaliers played perhaps their best game of the season when they routed Detroit 122-100 on Wednesday, but were eliminated from the playoff picture when the Celtics failed to hold a late lead in Atlanta later that night. The carryover from missing the postseason has shown in the last two games. The Cavaliers allowed 37 points in the first quarter and faltered down the stretch against the Bucks, who won for only the 15th time this season Friday.
Irving was 3 of 15 from the field and has shot 7-of-27 the last two games. Waiters was 6 of 15 from the field and both starting guards watched the final 12 minutes from the bench.
Rondo missed his second straight game after being kicked in the leg against Atlanta on Wednesday. Sullinger sprained his left ankle in the third quarter Friday, but returned and scored 20 points. The ankle became swollen overnight and the decision was made him to sit him out.
NOTES: Boston's last road win was over Milwaukee over two months ago. ... Cavaliers F Alonzo Gee picked up two fouls in the first 1:54 and went to the bench for the rest of the half. ... An MRI on Bayless' knee revealed a bruise and he may rejoin the team Monday in Philadelphia. ... Brown isn't sure if Deng, who has been banged up most of the season, will play in the final game Wednesday against New Jersey.