Master key

Master key may refer to:


 * Master keying, a special type of key designed to open multiple locks
 * Master Key, a pricing game on The Price Is Right
 * Knight's Armament Company Masterkey, a door breaching shotgun
 * One of the encryption keys used in a Master/Session encryption scheme
 * Master Key (TV series), a South Korean variety show
 * Master Key (Video Game) an independent video game by developer Achromi