We compared differences in self-concept change across three years after short-(STG) and long-term (LTG) psychodynamic group psychotherapy, in a mixed sample of outpatients. Self-concept was assessed at baseline and three years later, using the Structural Analysis of Social Behavior Questionnaire. Vector scores Affiliation and Autonomy were primary, and the eight cluster scores-self-free, self-affirm, self-love, self-protect, self-control, self-blame, self-attack, and self-neglect-were secondary outcome measures. Within group univariate analyses showed change in LTG across three years on the vector scores Affiliation and Autonomy, while STG only changed on Autonomy. Comparisons between STG and LTG demonstrated a significantly larger improvement in Affiliation in LTG than in STG. This difference was explained by a higher improvement in the cluster scores of self-blame, self-attack, and self-neglect in LTG, dimensions that weight negatively on the Affiliation score. Patients with more serious self-neglect and harsh, punitive self-attack/self-blame may profit more in long-term than in short-term groups.