This course surveys the historical and contemporary landscape of scientific research of psychedelic drugs within the field of psychology. The course begins with an introduction to psychedelic drugs and a brief overview of the anthropological literature regarding premodern, non-Western, and indigenous use of psychedelics. A history of the two “waves” of psychedelic research in modern psychology is then reviewed, the first of which took place roughly from the late 19th century through the mid-20th century and the second of which, sometimes called the “psychedelic renaissance,” began in the 1990s and is currently ongoing and rapidly expanding. The course then proceeds to examine research studies investigating the clinical use of psychedelics for the treatment of psychiatric conditions, with a focus on efficacy data across substances and disorders as well as on different treatment models of psychedelic-assisted psychotherapy that have been investigated. Psychedelic research in neuroscience, cognitive psychology, and social and personality psychology, as well as studies of psychedelic use in naturalistic (non-clinical) settings, is then discussed. The course concludes with an inquiry into issues of diversity, equity, and inclusion in psychedelic science, ethical issues in psychedelic science and psychedelic-assisted psychotherapy, and the future of psychedelics in psychology and in society.