This study investigated the relationship between multidimensional perfectionism, self-reported interpersonal relationships, and peer-reported prosocial, disruptive, and academic behaviors among a general sample of 984 9th-grade adolescents. Cut-scores from the "Almost Perfect Scale-Revised" (APS-R; Slaney, Rice, Mobley, Trippi, & Ashby, 2001) classified adolescents as adaptive perfectionists, maladaptive perfectionists, and nonperfectionist. Adaptive perfectionists reported significantly higher levels of positive interpersonal relationships than maladaptive perfectionists or nonperfectionists. Further, peers rated both perfectionism groups as more prosocial and less disruptive than nonperfectionists. Adaptive perfectionists were more liked than maladaptive perfectionists. Implications of these findings, particularly as they pertain to the nomothetic understanding of multidimensional perfectionism among older, school-aged adolescents conclude the paper. (Contains 2 tables.)