Although research in ecopsychology commonly identifies the value of spiritual experiences in nature for psychological well-being and environmental behaviour, previous research has not compared the outcomes of these experiences in natural and human-built settings. In the present study, the relationship between self-reported mystical experiences in natural and human-built environments for psychological wellbeing and environmental behaviour was investigated. A sample of 305 participants completed an amended version of Hood?s Mysticism Scale, a measure of psychological well-being, and brief environmental behaviour scale. Correlations indicated that mystical experiences in natural and in human-built environments both significantly predicted psychological well-being, but only mystical experiences in natural settings predicted environmental behaviour. This study suggests that mystical experiences in natural and human-built environments may be related to different outcomes.