Emerging research suggests that the use of serotonergic psychedelics may increase feelings of connection with the natural world. However, little is known about why this might be the case. Psychedelics often elicit self-transcendent positive emotions (STPE), and recent work has provided preliminary evidence suggesting that several of these emotions may have a causal influence on people's feelings of connectedness to the nature world, even when they are not elicited by nature. The present study aimed at extending this research into the context of psychedelics with the twin aims of furthering understanding regarding (a) the effects of STPE on connectedness to nature and (b) the psychological mechanisms through which psychedelics may increase feelings of connection to the natural world. Using an online retrospective survey, participants (N = 236) who had had a meaningful psychedelic experience in their life completed measures of (a) the acute effects of the meaningful psychedelic expe