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.

Diplomatic immunity is a principle of international law by which certain foreign government officials are recognized as having legal immunity from the jurisdiction of another country. It allows diplomats safe passage and freedom of travel in a host country and affords almost total protection from local lawsuits and prosecution.