Roger N. Walsh (born 1946) is an Australian professor of Psychiatry, Philosophy and Anthropology at the University of California, Irvine, in the Department of Psychiatry and Human Behavior, within UCI's College of Medicine. Walsh is respected for his views on psychoactive drugs and altered states of consciousness in relation with the religious/spiritual experience, and has been quoted in the media regarding psychology, spirituality, and the medical effects of meditation.