A gymslip is a sleeveless tunic with a pleated skirt most commonly seen as part of a girl's school uniform. The term gymslip primarily refers to athletic wear; otherwise the term pinafore dress (British English) or jumper dress (American English) is usually preferred.

The introduction of the gymslip as female athletic wear is credited to Martina Bergman-Österberg, the founder of a college for training female physical education teachers in Hampstead. Gymslips were also worn by female gymnasts and athletes from the 1880s to the 1920s, as they were more mobile than traditional female attire, but still modest enough to deter the possibility of them becoming sexualised during their activity. Even in this modest attire, gymslips as athletic wear were still worn strictly out of public view.

When not worn as athletic wear, gymslips or pinafore dresses are generally worn over a blouse and tie and replace a skirt. Underneath a gymslip, a pair of white knee socks are more common than a pair of tights, matching regulation knickers may also be mandatory. A blazer may be worn over the top. First emerging in the 1900s, by the 1920s it had become compulsory in many private, convent and high schools, and thus became commonly worn by girls in Britain as part of their school uniform.