The Fabulous Furry Freak Brothers are a trio of underground comic strip characters created by the U.S. artist Gilbert Shelton. Beginning in 1968, their adventures were collected in a series of underground comics published by Rip Off Press. With the demise of the underground newspaper, new adventures continued to appear in magazines such as Playboy, High Times, and Rip Off Comix, and these too were collected in comic book form. Shelton continued to write the series until 1992, in collaboration with Dave Sheridan (1974-1982) and Paul Mavrides (since 1978). The work enjoys a sizeable cult following.

The comics relate the humorous adventures of the eponymous "brothers" and, more often than not, their attempts to procure drugs and avoid apprehension by the police. The stories are highly satirical in nature and often poke fun at the establishment and right-wing politics. For a counterculture production, the standard of artwork is exceptionally high; Shelton's striving for accuracy and attention to detail have earned him comparisons with Hergé.

The majority of the titles in the series consist of one or more multi-page stories together with a number of one-page strips. Many of the later have a one-row skit featuring Fat Freddy's Cat at the bottom of the page. Some of the titles also contain a small number of strips featuring completely unrelated characters.