N,N-Dimethyltryptamine (DMT or N,N-DMT, SPL026) is a substituted tryptamine that occurs in many plants and animals, including humans, and which is both a derivative and a structural analog of tryptamine. It is used as a psychedelic drug and prepared by various cultures for ritual purposes as an entheogen.

DMT has a rapid onset, intense effects, and a relatively short duration of action. For those reasons, DMT was known as the "businessman's trip" during the 1960s in the United States, as a user could access the full depth of a psychedelic experience in considerably less time than with other substances such as LSD or psilocybin mushrooms. DMT can be inhaled, ingested, or injected and its effects depend on the dose, as well as the mode of administration. When inhaled or injected, the effects last a short period of time: about five to 15 minutes. Effects can last three hours or more when orally ingested along with a monoamine oxidase inhibitor (MAOI), such as the ayahuasca brew of many native Amazonian tribes. DMT can produce vivid "projections" of mystical experiences involving euphoria and dynamic pseudohallucinations of geometric forms.

DMT is a functional analog and structural analog of other psychedelic tryptamines such as O-acetylpsilocin (4-AcO-DMT), psilocybin (4-PO-DMT), psilocin (4-HO-DMT), O-methylbufotenin (5-MeO-DMT), and bufotenin (5-HO-DMT). Parts of the structure of DMT occur within some important biomolecules like serotonin and melatonin, making them structural analogs of DMT.