Ibaka went to the floor after the two were battling for position under Cleveland's basket as the Raptors attempted a full-court pass that sailed out of bounds.
Ibaka shoved Chriss from behind and grabbed near his neck before throwing a punch. Chriss responded with a punch before players from both teams separated the two. Ibaka immediately headed for the locker room, and both players were kicked out after the officials conferred.
Cleveland was winning 91-77 at the time of the incident and went on to win 126-101.
Earlier in the game, Ibaka had hit the court hard in the second quarter after being fouled by Chriss following a rebound.
Neither player was available for comment following the game. A Raptors spokesman said Ibaka was reacting to something Chriss said to him after Ibaka was knocked to the floor.
Monday's game marked the eighth ejection of Ibaka's 10-year career and the third for Chriss in three seasons.
As a repeat offender, Ibaka could be facing a suspension in the range of three to five games, according to ESPN front-office insider Bobby Marks. Ibaka would lose about $149,000 for every game he misses.
The Associated Press contributed to this report.