XS: The Worst Size (Spanish: XS, la peor talla) is a 2003 Chilean comedy film directed by Jorge López Sotomayor and written by Gonzalo Maza & Luis Ponce. It is based on the short story of the same name by Sergio Gómez. It stars Benjamín Vicuña, Gonzalo Valenzuela and María Elena Swett. It premiered on November 27, 2003, in Chilean theaters.

The film started as a telefilm for the National Television series Cuentos Chilenos in 1999, but was later transformed into a theatrical feature film.