Oththa Seruppu Size 7 (transl. Single Slipper Size 7), simply known as Oththa Seruppu (transl. Single Slipper), is a 2019 Indian Tamil-language thriller film produced, written and directed by R. Parthiban under the banner Bioscope Film Framers. The film stars Parthiban himself as the only character. The background score for the film is composed by C. Sathya and the film has only one song, which is composed by Santhosh Narayanan. The film entered the Asia Book of Records and India Book of Records for having a single person writing, directing, solo acting and producing a film. It was the third South Indian film to feature a single actor after The Guard (2001- Malayalam) and Shanti (2005- Kannada).

Oththa Seruppu premiered at the Singapore South Asian Film Festival on 30 August 2019. The film was released worldwide on 20 September 2019.The film opened to high critical acclaim.

It is being remade in Hindi with Abhishek Bachchan in the lead role and directed by Parthiban. The movie was also reported to be remade in Indonesian making it the first Tamil movie to be remade in that language and the second Indian movie to be remade in that language after Drishyam.