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 or high commission, 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. 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.

Diplomacy comprises spoken or written communication by representatives of state, intergovernmental, or nongovernmental institutions intended to influence events in the international system.