Psilocybin is emerging as a novel and effective treatment for a variety of mental illnesses when administered in a psychologically supportive clinical setting. This systematized review sought to determine the role of therapists in psilocybin-assisted psychotherapy (PAP), a term used in the literature to describe the administration of psilocybin in the context of treating mental illness. The role of therapists was determined through an investigation of the structure and content of PAP. Briefly, the review found substantial homogeneity in the structure of PAP across the collected studies, but substantial heterogeneity in PAP's content. Psychotherapy modalities and techniques implemented in PAP are reviewed and discussed, as well as implications for therapists interested in PAP.