The Earl of Fife or Mormaer of Fife was the ruler of the province of Fife in medieval Scotland, which encompassed the modern counties of Fife and Kinross. Due to their royal ancestry, the earls of Fife were the highest ranking nobles in the realm, and had the right to crown the king of Scots.

Fife is a council area, historic county, registration county and lieutenancy area of Scotland. It is situated between the Firth of Tay and the Firth of Forth, with inland boundaries with Perth and Kinross and Clackmannanshire. By custom it is widely held to have been one of the major Pictish kingdoms, known as Fib, and is still commonly known as the Kingdom of Fife within Scotland. A person from Fife is known as a Fifer. In older documents the county was very occasionally known by the anglicisation Fifeshire.