A review of personal and family variables that regulate prosocial behavior is based on a sample of 1,433 Spanish adolescents (ages 9 to 13; 743 boys and 690 girls) who were assessed on the Prosocial Reasoning Objective Measure, the Physical and Verbal Aggression Scale, the Emotional Instability Scale, the State-Trait Anger Inventory, the Child's Report of Parental Behavior Inventory, the Prosocial Behavior Scale, and the Index of Empathy for Children and Adolescents. Discriminant analyses showed that empathy, self-control in anger-provoking situations, and affection in family relationships are the best predictors of prosocial behavior.