William Klein

Bill, Will, Willy, Willie or William Klein may refer to:


 * William Klein (photographer) (1926–2022), American-French photojournalist and filmmaker
 * Will Klein (baseball) (born 1999), pitcher in the Kansas City Royals organization
 * Willie Klein (1901–1957), American champion golfer
 * Willy Klein (1912–2004), Luxembourgian Olympic gymnast in 1936
 * Bill Klein (businessman) (born 1948), American high-stakes poker champion
 * Bill Klein, American football end in 1950 NFL Draft
 * Bill Klein, American businessman on 2009 TV reality series The Little Couple