Dr. Octagonecologyst is the debut solo studio album by American rapper and Ultramagnetic MCs member Kool Keith, released under the alias Dr. Octagon. Originally titled Dr. Octagon, it was released on May 7, 1996, on Bulk Recordings in the United States and Mo' Wax in the United Kingdom. The album was reissued with a different track listing by DreamWorks Records in 1997 under the title Dr. Octagonecologyst. The album was produced by Dan "The Automator" Nakamura and featured the work of turntablist DJ Qbert. KutMasta Kurt provided additional production work. The artwork for Dr. Octagonecologyst was drawn by Brian "Pushead" Schroeder.

Dr. Octagonecologyst introduces the character of Dr. Octagon, a homicidal, extraterrestrial, time-traveling gynecologist and surgeon. The album's distinctive sound fuses genres such as psychedelic music, trip hop and electronic music. Thornton's lyrics are often abstract, absurd, and avant-garde, using surrealism, non-sequiturs, hallucinatory psychedelia, and horror and science-fiction imagery, as well as sexual humor, absurdist/surrealistic humor, and juvenile humor.

Kool Keith's lyrics and Nakamura's production were highly praised, as was DJ Qbert's innovative scratching. Dr. Octagonecologyst has since been ranked as one of the best hip hop albums of the 1990s. The character of Dr. Octagon has also appeared in Kool Keith projects like First Come, First Served (1999) and Dr. Dooom 2 (2008), both of which contain tracks in which Octagon is murdered by Dr. Dooom, The Return of Dr. Octagon, Moosebumps: An Exploration Into Modern Day Horripilation and Space Goretex. Kool Keith later stated that the album sold around 200,000 copies without any major promotion or marketing budget.