A matchmaking system matches players for online gaming, when some of the players may be human players and others may be simulated players. The matchmaking system may determine a first skill score associated with a first player for an online game, determine a behavior simulation model for a simulated player is available for the online game, determine a second skill score associated with the behavior simulation model for the online game, and determine the behavior simulation model matches with the first player based at on the first skill score being within a threshold of the second skill score. The matchmaking system may then instantiate a simulated player based on the behavior simulation model and instantiate the online game with the first player and the simulated player.