Results show that the likelihood ratings for all forms of aggression were very low, substantiating the belief that most spectators at youth sports events do not behave aggressively at such events. A number of parents in the sample did indicate some likelihood of engaging in verbal or emotional aggression despite the zero tolerance of their leagues. The likelihood of yelling at and humiliating others was greater than physical aggression and swearing at others. Consistent with previous research, the likelihood of reported spectator aggression was not predicted by a past history of physical or verbal aggression, which suggests that aggressive spectators are more than simply aggressive individuals. The study did show that hostility and anger, which are components of trait aggression, predicted subtypes of spectator aggression. Spectator aggression may be an expression of a vengeful attitude, since vengeful spectators reported a greater likelihood of humiliating umpires based on a perception of injustice or unfairness. Men were the primary perpetrators. Participants were 76 mothers and 52 fathers from 2 youth baseball leagues in western New York. Both leagues have a "zero-tolerance" policy on spectator aggression. The sample was administered the Vengeance Questionnaire (Stuckless and Goranson, 1992) and the Aggression Questionnaire (Buss and Perry, 1992). In order to measure spectator aggression, participants were presented a list of seven potential targets of spectator aggression at youth baseball games. 5 tables and 56 references