A jockstrap, strap, cup, groin guard, supporter, or athletic supporter, is an undergarment for protecting the testes and penis (for boys and men) during contact sports or other vigorous physical activity. This article deals chiefly with the genital protective sports gear designed for the male body, colloquially known as a "jock".

A jockstrap consists of a waistband (usually elastic) with a support pouch for the genitalia and two elastic straps affixed to the base of the pouch and to the left and right sides of the waistband at the hip. The pouch, in some varieties, may be fitted with a pocket to hold an abdominal guard (impact resistant cup, box) to protect the testicles and the penis from injury.

The jockstrap was invented in 1874 by C. F. Bennett of a Chicago sporting goods company, Sharp & Smith, to provide comfort and support for bicycle jockeys working the cobblestone streets of Boston. In 1897 Bennett's newly formed Bike Web Company patented and began mass-producing the Bike Jockey Strap.

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