The purpose of this study was to explore gender differences in the forms of aggression experienced by and perpetrated on Taiwanese adolescents, and to examine the relationship between aggression and peer rejection during adolescence. The participants consisted of 2211 adolescents (1127 boys and 1084 girls) from 62 classrooms of 13 junior high schools in Taipei area. A peer nomination procedure was used to obtain each participant’s aggression scores and sociometric status. The number of nominations received for each item was further standardized within each classroom and used for further analyses. The findings show a gender effect in two forms of aggression – relational and overt aggression: (1) Girls were significantly more relationally aggressive than boys, whereas boys were significantly more overtly aggressive than girls; and (2) Ninety-five percent of adolescents in the overt-aggression group were boys and eighty-three percent of adolescents in the relational-aggression group were girls. The results also demonstrated that both relational and overt aggression were predictive of concurrent peer rejection in this sample of adolescents. Relational aggression was the highest in adolescents of controversial status than in all the other groups (i.e., rejected, average, popular, neglected). Thus, the study demonstrates that relational aggression is favored by female adolescents and it is a salient factor of peer rejection.