This Boys' Town paper for parents examines the reactive aggression of children who respond aggressively to what they view as provocation. The paper differentiates between reactive and proactive aggression by presenting examples of each. Factors that can increase aggression in families are noted, including punishment acceleration, crossover, counterattacks, continuance, synchronicity, multiple effects, and issue transfer. The paper argues that it is important to identify which contingencies are present in the family and find ways to change the interactions so that alternative behaviors are used and aggression is not promoted. Several effective methods are detailed for promoting positive alternative behaviors, including giving a consequence, giving simple instructions, using empathy to show understanding of the child's feelings, giving an other-centered rationale, and giving a statement of the seriousness of the offense. The paper discusses types of distorted thinking that can lead to reactive aggression, including filtering, overgeneralization, mind-reading, personalization, control fallacies, fallacy of fairness, blaming, and heaven's reward fallacy. Methods to help children change distorted thinking are then detailed, including describing the situation or event, helping the child identify his or her thoughts, changing the distortion, and using thought-stopping. The paper concludes that preventive teaching and teaching children the difference between their emotions and their behavior are methods to help children deal with situations that often lead to aggression, such as teasing, getting criticized, and being rejected. Adults can also help the child remain calm in difficult situations. (KB)