PURPOSE OF THE STUDY: Psilocybin is a rapidly-emerging treatment for depression, yet its impact on sleep is not well understood. We sought to explore the literature on sleep and psilocybin use, and explore the topic using our own primary data. FINDINGS: Whilst clinical trials demonstrate large depressive symptom improvements, the impact of psilocybin on sleep quality or insomnia symptoms, has not been directly studied. Using our own preliminary-data we demonstrated that both depressive-symptoms and sleep-disturbances decreased significantly following psilocybin use, though sleep improvements were smaller compared to depressive symptoms. More severe sleep-disturbances at baseline were linked to lower probability of depression remission, underscoring a potential interaction between sleep and psilocybin's efficacy. Addressing sleep disturbances could enhance therapeutic outcomes in psilocybin-assisted therapy and could lead to more effective, personalized treatment-strategies. Future research should focus on populations with sleep disorders, and on examining causal-pathways of sleep physiology's impact on psilocybin efficacy.