Expanding on the work of Forstmann and Sagioglou, this study investigated the differences in personality and pro-environmental behavior (PEB) as a function of psychedelic-occasioned mystical experiences. A sample of 240 participants with prior psychedelic experience completed an online survey. Data were collected on participants’ psychedelic-occasioned mystical states, personality, and self-reported PEB. A measure of behavioral PEB was also included (Charity Task). The mean scores on self-reported PEB, openness and agreeableness of participants who met the criteria for a “complete” mystical state, were significantly higher than those who did not. Specifically, those who experienced a mystical state scored higher on the PEB types “eco-shopping and eating” and “one-off domestic conservation actions.” Participants who demonstrated PEB in the Charity Task scored higher on self-reported PEB than those who did not, supporting the task’s validity. Findings suggest that mystical experiences influence PEB. Future research with experimental designs could further illuminate potential causal relationships.