The article examines sexual functioning as a promising domain for identifying outcome indicators in psychotherapy research for personality disorders. Contemporary dimensional models, such as the DSM-5 Alternative Model for Personality Disorders and the ICD-11, consistently identify impairments in emotion regulation, identity, and interpersonal functioning as central features of these disorders. Despite sexuality being profoundly linked to these core areas, both conceptually and clinically, it remains largely neglected in personality disorders psychotherapy research. The article begins with a review of empirical evidence demonstrating associations between personality pathology and various sexual difficulties, including dysfunctions, impulsivity, and relational problems. The degree to which established psychotherapeutic approaches – transference-focused psychotherapy, mentalisation-based treatment, dialectical behaviour therapy, and schema-focused therapy – address sexual functioning, whether explicitly or through their broader mechanisms of change, is then examined. Building on Bancroft’s developmental model of sexuality, a structured framework of sexuality-related outcome indicators is proposed for integration into future psychotherapy research. These indicators are aligned with key therapeutic targets in personality disorder treatment, including improvements in self-concept, affect regulation, and interpersonal functioning. It is argued that including sexual functioning as an outcome measure in research on the effectiveness of psychotherapy for personality disorders will allow for a deeper and more comprehensive understanding of its therapeutic potential. The article presents the theoretical and empirical foundations of this proposal and discusses its possible applications in research design.