A diplomatic mission or foreign mission is a group of people from a state or organization present in another state to represent the sending state or organization officially in the receiving or host state. In practice, the phrase usually denotes an embassy, which is the main office of a country's diplomatic representatives to another country; it is usually, but not necessarily, based in the receiving state's capital city. Consulates, on the other hand, are smaller diplomatic missions that are normally located in major cities of the receiving state (but can be located in the capital, typically when the sending country has no embassy in the receiving state). As well as being a diplomatic mission to the country in which it is situated, an embassy may also be a nonresident permanent mission to one or more other countries.

The term embassy is sometimes used interchangeably with chancery, the physical office or site of a diplomatic mission. Consequently, the terms "embassy residence" and "embassy office" are used to distinguish between the ambassador's residence and the chancery.