This chapter presents a neurophenomenological model of psychedelic-induced transpersonal experiences, therapeutic processes that they induce, and their implications for transpersonal theory. The pharmacological effects of psychedelics also enable them to address a range of psychological and emotional maladies. In addition to indigenous and shamanic approaches, there are four main types of psychedelic sessions: psycholytic and psychedelic—which developed from Grof’s work—entactogenic, and pharmacological. While it is safe to say that transpersonal psychology could exist without psychedelics, it may be just as safe to say that transpersonal psychology would not exist without psychedelics. The chapter concludes with a brief overview of the multidisciplinary implications of psychedelics for the sciences and society.