Objective. We examined the role of expressed self-contempt in therapy for borderline personality disorder (BPD). Based on previous literature on BPD, we assumed an association between the self-contempt and the core symptoms of BPD. We also studied the progression of expressed self-contempt during the treatment and its effect on the alliance and the outcomes of treatment.Method. We rated the expressed self-contempt in 148 tape-recorded sessions with patients with BPD (N = 50), during a brief psychiatric treatment. We rated self-contempt at three time-points, using an observer-rate scale. Self-reported questionnaires were used to assess symptoms and the working alliance.Results. There are some associations between self-contempt and BPD symptoms. Expressed self-contempt did not change during the treatment. One measure of self-contempt was associated with a weaker alliance rated by the patients and with a stronger alliance rated by the therapists. The expression of high self-contempt was not predictive of outcomes when the initial level of problems was controlled for.Conclusions. The results highlight the importance to examine the complex effects of self-contempt in BPD undergoing treatment in a differentiated manner and suggest to clinicians and researchers to be attentive to this specific emotional state, and change therein, in psychotherapy.Keywords: Self-contempt; Borderline Personality Disorder; Brief Treatment; Therapeutic Alliance; EmotionTrial registration: ClinicalTrials.gov identifier: NCT01896024.