The present study examined the effects of an aggressor's authority on preschoolers' judgments about aggressive behavior. Preschoolers (28 boys, 37 girls ; average age 57 months; age ranging from 33 to 82 months) were presented with six picture stories in which the main character (authoritative character: teacher, unauthoritative character : child) showed either provocative, retaliative, or punitive aggressive behavior. Following each story, the children were asked to judge whether the aggressive behavior was right or wrong. The results were as follows: (1) Children in younger group (age ranging from 33 to 47 months) judged all types of aggression to be wrong ; however, those in middle (age ranging from 48 to 59 months) and older (age ranging from 60 to 82 months) groups allowed retaliative and punitive aggression but judged provocative aggression to be wrong. (2) Regardless of type, teachers' aggressions were more allowed than children's aggressions by every age. The results indicate that although judgments of the children in middle and older groups are based on the concepts of harm and justice, these judgments are affected by the aggressor's authority.