Background Prior research indicates that patients' personality traits are associated with psychotherapy processes and outcomes. However, the potential relevance of therapists' personality traits is less understood. Methods This is a scoping review of studies investigating associations between therapists' personality traits with treatment processes and outcomes. Three databases (Scopus, PsycINFO, and Web of Science) were searched, identifying 27 eligible studies synthesized using a narrative review of key findings. Results The influence of therapists' personality traits was studied in relation to therapeutic orientation, interpersonal skills, therapist competence and skill, model fidelity, treatment outcomes, therapeutic alliance, and therapist well‐being. Findings indicate that therapists' personality traits are associated with the choice of therapeutic orientation and with interpersonal skills, but there is mixed evidence about associations with clinical outcomes. Conclusion Therapists' personality traits are associated with therapeutic orientation and interpersonal skills. However, it remains unclear whether therapists' personality traits influence other aspects of therapeutic processes or outcomes.