This study examined changes in adolescents' internal representations of their relationship with their therapist and the extent to which these changes were related to changes in their representations of their relationship with their parents and to treatment outcomes. MethodThirty adolescents (aged 15–18 years, 70% women) undergoing psychodynamic psychotherapy participated in relationship anecdote paradigms interviews based on the core conflictual relationship theme method and completed outcome measures at the beginning of treatment and a year later. ResultsAdolescents' positive representations of their therapists increased throughout the year of treatment, whereas their negative representations did not change. There was an association between the development of the therapeutic relationship and improvement in the perception of the relationship with parents over the course of therapy. Increases in the level of positive representations and decreases in the level of negative representations of the therapist were associated with greater satisfaction with treatment but not with the other outcome measures. These results support the centrality of the therapeutic relationship in the process of change during adolescents' psychodynamic psychotherapy. Copyright © 2014 John Wiley & Sons, Ltd. Key Practitioner Message The finding that positive representations of the therapist increased throughout treatment but that negative representations remained steady suggests that therapists who treat adolescents should expect and be able to hear adolescent clients' positive and negative internal representations of themselves. Therapists need to realize that although adolescents often experience negative emotions and perceptions in therapy as in other significant relationships, this does not necessarily block the development of positive emotions. The finding that changes in the representations of the therapist are associated with changes in the representations of parents is in line with psychodynamic theory, which posits that psychotherapy facilitates new interpersonal experiences and new insights through the exploration of the therapeutic relationship. Working in the ‘here and now’ may eventually impact the nature of other significant relationships, particularly with parents in the case of adolescents.