Parents from two baseball leagues completed questionnaires regarding their likelihood of engaging in various aggressive behaviors (yelling, swearing, shoving, fighting, humiliating) toward targets at youth baseball games (other spectators, umpires, coaches, other players, their child). Overall, the likelihood of all forms of aggression was very low, particularly physical aggression and swearing. Hierarchical entry stepwise regressions were calculated to determine predictors of yelling and humiliating using demographics, trait aggression, anger, hostility, and vengeance as predictors. Parents with greater hostility reported a greater likelihood of humiliating a child's teammate, while those with elevated trait anger reported a greater likelihood of yelling at other spectators. Finally, parents with a more vengeful attitude reported a greater likelihood of humiliating umpires.