A master of ceremonies, abbreviated MC or emcee, is the official host of a ceremony, staged event, conference, convention, or similar performance.

The term is earliest documented in the Catholic Church since the 5th century, where the master of ceremonies is an official of the Papal Court responsible for the proper and smooth conduct of the elaborate rituals involving the pope and the sacred liturgy.

The master of ceremonies sometimes also refers to the protocol officer during an official state function, especially in monarchies.

Today, the term is often used to connote a person who presents performers, speaks to the audience, entertains people, and generally keeps an event moving. This usage occurs in the entertainment industry, for example in reference to television game show hosts, as well as in contemporary hip hop and electronic dance music culture.

In addition, the term also exists in various chivalric orders and fraternal orders.