Abstract Game behaviors affect gamers’ psychological and behavioral development in real life. Previous studies have shown that demographic and basic personality traits are associated with game behaviors in massively multiplayer online role-playing games. However, little is known about the roles of trait aggression and game motivations, especially in multiplayer online battle arena games. Thus, the aim of this study was to investigate how demographic, trait aggression, and game motivations affect multiplayer online battle arena game behaviors. A total of 1,316 Chinese adolescent gamers who play Honor of Kings responded to questions related to demographic information, trait aggression, game motivations (socializer, competitor, escapist, story-driven, completionist, and smart-enhance), and game behaviors (aggressing, winning, creating, and helping). The multiple linear regression model results showed that males, socializers, completionists, and smart-enhance were more likely to exhibit aggressing, winning, creating, and helping behaviors. Trait aggression predicted aggressing, winning, and creating behaviors. Moreover, age and competitor scale positively predicted aggressing and winning behaviors. Meanwhile, escapists tended to engage in aggressing and creating behaviors, and story-driven players exhibited creating and helping behaviors. These results may be useful in explaining individual differences in game behaviors and the relationships between video-game and real-life behaviors for gamers.