The Smashing Bird I Used to Know is a 1969 British drama/sexploitation film, directed by Robert Hartford-Davis and starring Renée Asherson, Patrick Mower, Dennis Waterman, Madeleine Hinde and Maureen Lipman. As with other Hartford-Davis films, The Smashing Bird I Used to Know contains elements from different genres including psychological drama and social commentary. It is best known however as a sexploitation piece featuring nudity, attempted rape and lesbianism. The film features the first screen credit of the then 15-year-old Lesley-Anne Down in a supporting role.The film was not released in the U.S. until 1973, retitled by AIP as School for Unclaimed Girls. More recent issues of the film in the UK have also used this title as being less dated and more indicative of the film's content AIP also reissued the film a year later under their shadow company United Producers Organization as Hell House Girls.

A scene outside a cinema shows the poster for Hartford-Davis’ previous film Corruption starring Peter Cushing in the background. The village and interior designer shop where Peter works was filmed in Petworth in West Sussex.