A bra, short for brassiere or brassière (US: , UK: or ; French: [bʁasjɛʁ]), is a form-fitting undergarment that is primarily used to support and cover women's breasts. A typical bra consists of a chest band that wraps around the torso, supporting two breast cups that are held in place by shoulder straps. A bra usually fastens in the back, using a hook and eye fastener, although bras are available in a large range of styles and sizes, including front-fastening and backless designs. Some bras are designed for specific functions, such as nursing bras to facilitate breastfeeding or sports bras to minimize discomfort during exercise.

Although women in ancient Greece and Rome wore garments to support their breasts, the first modern bra is attributed to 19-year-old Mary Phelps Jacob (later and better known as the New York publisher and activist Caresse Crosby) who created the garment in 1913 by using two handkerchiefs and some ribbon. After patenting her design in 1914, she briefly manufactured bras at a two-woman factory in Boston before selling her patent to the Warner Brothers Corset Company, which began mass-producing the garment. The bra gained widespread adoption during the first half of the twentieth century, when it largely replaced the corset. The majority of Western women today wear bras, with a minority choosing to go braless. Bra manufacturing and retailing are key components of the multi-billion-dollar global lingerie industry.