Janet Arnold (6 October 1932 – 2 November 1998) was a British clothing historian, costume designer, teacher, conservator, and author. She is best known for her series of works called Patterns of Fashion, which included accurate scale sewing patterns, used by museums and theatres alike. She went on to write A Handbook of Costume, a book on the primary sources on costume study, and Queen Elizabeth's Wardrobe Unlock'd, as well as many other books.