A jumper (in American English), jumper dress, or pinafore dress^[1][2] is a sleeveless, collarless dress intended to be worn over a blouse, shirt, T-shirt or sweater.^[3][4][5] Hemlines can be of different lengths and the type of collar and whether or not there is pleating are also variables in the design.^[6]

In British English, the term jumper describes what is called a sweater in American English. Also, in more formal British usage, a distinction is made between a pinafore dress and a pinafore. The latter, though a related garment, has an open back and is worn as an apron. In American English, pinafore always refers to an apron.^{[citation needed]}

A sundress, like a jumper, is sleeveless and collarless; however, such articles are not worn over a blouse or sweater, and are of distinctly different cuts and fashions. The apron dress may be viewed as a special case of the jumper. If the design of the dress is directly inspired by an apron (having a bib in front and ties in the back, for example), the garment is typically described as an apron dress.^[7]

Jumpers for fall were described in The Fort Wayne Sentinel in 1906.^[8] The dresses were "imported from Paris" and featured "original lines."^[8]

Jumpers in the United States were part of the sportswear collections of Jean Patou, Coco Chanel and Paul Poiret.^[6] Suzanne Lenglen wore Patou's jumper design in the 1920s.^[6] The dresses, worn over blouses, became popular during the decade of the 1920s.^[9] Jumpers were often worn in the summer and made out of various types of fabrics.^[10]

Jumpers were touted as an "American" and a "sports fashion" in 1930 by the Pittsburgh Press.^[11] The dresses were also praised for allowing women to create color combinations through the choice of blouse worn underneath.^[11]

Jumpers were again popularized in 1953, when Hubert de Givenchy promoted his own jumper.^[12] Jumpers, now considered a "classic" look, were considered "suitable to all ages."^[13]

• Gymslip – a British pinafore dress worn as athletic wear or school uniform
• Kirtle – a medieval garment of similar function
• Romper suit – combination of shorts and shirt
• Sarafan – a Russian traditional jumper dress