Abstract Background and aims Most modern modalities of psychedelic-assisted psychotherapy (PAP) aim to minimize harm and maximize support by utilizing close, formalized supervision for a single participant per session. However, these substances are used naturalistically in a wide variety of settings. Our goal was to evaluate the perceived benefits and harms of naturalistic psychedelic use in diverse settings, with and without guidance/supervision. Methods An anonymous survey was distributed over Internet forums to solicit responses from English-speaking adults, with questions regarding the setting and perceived mental health-related outcomes of classic psychedelics. Data were analyzed to compare effects of group versus solo setting on perceived outcomes. Results For the goal of improving mental health, use in a solo setting was more common than in a group setting (COR 0.37 (0.20–0.68), p = 0.03) and was associated with more subjective symptom improvement (COR 0.22 (0.11–0.42), p = 0.0002). However, there was no significant difference in perceived overall mental health benefit between use in group and solo settings (p = 1). Subjective negative outcomes on mental health were rare and not associated more so with psychedelic use in any particular setting. A majority of naturalistic psychedelic use took place in an informal setting, with no significant difference between solo or group users (95% vs 91%, p = 0.3). Conclusions Naturalistic psychedelic users are as likely to report an overall positive outcome and no more likely to report adverse events in group settings than in solo settings. This supports further research into PAP in group settings.