The Other Side of the Underneath is a 1972 British experimental psychological drama film written and directed by Jane Arden and starring Sheila Allen, Liz Danciger, Penny Slinger, Ann Lynn, and Suzanka Fraey. Other members of the Holocaust Theatre Company appear in the film. Jane Arden herself also appears in the film.

It is the only British feature film in the 1970s to be solely directed by a woman. The title of the film is taken from a line in Arden's play Vagina Rex and the Gas Oven, which was a huge success at the London Arts Lab in 1969. The film is an adaptation of Arden's 1971 play A New Communion for Freaks, Prophets and Witches. The film had almost mythical status amongst fans of radical, experimental cinema, partly because of its visionary and disturbing depictions of the mental state of its schizophrenic protagonist, and also its unavailability.