Cashmere wool, usually simply known as cashmere, is a fiber obtained from cashmere goats, pashmina goats, and some other breeds of goat. It has been used to make yarn, textiles and clothing for hundreds of years. Cashmere is closely associated with the Kashmir shawl, the word "cashmere" deriving from an anglicization of Kashmir, when the Kashmir shawl reached Europe in the 19th century. Both the soft undercoat and the guard hairs may be used; the softer hair is reserved for textiles, while the coarse guard hair is used for brushes and other non-apparel purposes.

A number of countries produce cashmere and have improved processing techniques over the years but China and Mongolia are two of the leading producers as of 2019. Afghanistan is ranked third.

Some yarns and clothing marketed as containing cashmere have been found to contain little to no cashmere fiber, so more stringent testing has been requested to make sure items are fairly represented. Poor land management and overgrazing to increase production of the valuable fiber has resulted in the decimation and transformation of grasslands into deserts in Asia, increasing local temperatures and causing air pollution which has traveled as far as Canada and the United States.