This study tested models of perfectionism predicting psychological distress and academic adjustment and moderators and mediators of those associations in 2 successive cohorts of high-achieving university honors students (N = 499). Participants completed measures earl and late in the semester. Adaptive (high standards) and maladaptive (self-critical perceptions of inadequacy in meeting performance expectations) dimensions of perfectionism were found to be significantly associated, in generally expected directions, with concurrent and prospective perceived stress, social connectedness, depression, hopelessness, and perceived academic adjustment. However, some perfectionism effects were reduced when earlier psychological distress and adjustment were controlled in analyses predicting later distress and adjustment. Several effects were moderated and at least partially mediated by perceived stress and social connection. The results suggest several counseling implications for high-achieving, perfectionistic students.