According to Blatt’s theory on personality development, adolescents with high levels of self-criticism and dependency are more vulnerable to diverse types of psychopathology. However, relatively little is known about intervening processes involved in this personality-based vulnerability. The goal of this study is to examine, on the basis of Self-Determination Theory, the explanatory role of the psychological needs for autonomy, competence, and relatedness in associations between self-criticism and dependency on the one hand and adolescents’ internalizing and externalizing problems on the other hand. In this cross-sectional and multi-informant study, 284 adolescents (58,5% female; mean age = 14.15; SD = .93) and their parents reported about the adolescent’s internalizing and externalizing problems. Adolescents also completed measures assessing self-criticism, dependency, and psychological needs experiences. Data were analyzed using structural equation modeling. Self-criticism and dependency were significantly related to higher levels of both internalizing and externalizing problems, with psychological need frustration fully mediating these associations. This study suggests that psychological need frustration is an important explanatory mechanism in personality-related vulnerability for adolescent psychopathology. More generally, it provides further evidence for the integration between two major theoretical approaches in the domain of adolescent development and psychopathology.