ABSTRACT The present study probed the links among Big Five personality differences, self-reported personality differences, and adjustment to school among young adolescents. We used a multimethod converging analysis, with three sources of data: (a) adolescent self-report on standardized personality inventories; (b) classroom teacher trait ratings and evaluations of adjustment; and (c) school guidance counselor evaluations of adjustment. Evaluations of adolescent adjustment were systematically related to Big Five personality differences, as assessed by both classroom teachers' and school counselors' ratings. For classroom teachers, adjustment was closely related to evaluations on the Big Five dimension of Conscientiousness. Adolescent self-report on several standardized measures was not related to adult evaluation of school adjustment. We suggest that the five-factor model may be a useful tool for probing adjustment during the transition to adolescence.