Guilt serves vital prosocial functions: It motivates transgressors to make amends, thus restoring damaged relationships. Previous developmental research on guilt has not clearly distinguished it from sympathy for a victim or a tendency to repair damage in general. The authors tested 2- and 3-year-old children (N = 62 and 64, respectively) in a 2 × 2 design, varying whether or not a mishap caused harm to someone and whether children themselves caused that mishap. Three-year-olds showed greatest reparative behavior when "they" had caused the mishap "and" it caused harm, thus showing a specific effect of guilt. Two-year-olds repaired more whenever harm was caused, no matter by whom, thus showing only an effect of sympathy. Guilt as a distinct motivator of prosocial behavior thus emerges by at least 3 years.