There is a growing base of research supporting the therapeutic efficacy of classic psychedelics in treating various clinical conditions, although more work is needed to clarify the psychological mechanisms underpinning these effects. The psychological flexibility model is an established psychological framework linked to wellbeing and mental health. Aim/ To determine whether psychological rigidity/experiential avoidance changes following a psychedelic experience. Method/ A web survey (www.psychedelicsurvery.com) was used in a prospective way to measure changes in psychological rigidity (AAQ-II) before versus after a self-reported psychedelic experience. 160 respondents completed the survey which also included measures of depressive symptomology (QIDS) and subjective experience (MEQ-30, EBI). Results/ Significant decreases in AAQ-II scores were observed at one week and four weeks post experience (t (159) = 4.15, p < 0.001). Changes in AAQ-II scores peaked at one week and correlated with changes in QIDS scores (r = 0.24, p = 0.002). Conclusion These results suggest that psychological flexibility is enhanced after a psychedelic experience. Psychological flexibility is a phenomenon that is closely related to the Acceptance and Commitment Therapy (ACT) model of psychotherapy. We conclude that these data support the view that ACT may offer a complementary model to psychedelic therapy. We encourage efforts to integrate ACT and psychedelic therapy, for mutual benefit.