Residence of an ambassador posted to a foreign country's capital city. However the term now commonly includes buildings where diplomats carry out their business, known as a chancery. From embassies, diplomats carry out various duties of representing their country's government to the host government and people, promoting their nation's interests and expanding bilateral relationships. And, on occasion, engage in espionage.

An embassy can also be headed by a charge d'affaires on a temporary basis, or more permanently if for whatever reason the sending state has not thought an ambassador would not be suitable. The Holy See dispatches nuncios. In some cases where diplomatic relations have been severed, a country may still carry on its work through the premises of a third party country.

Countries of the British Commonwealth call their diplomatic missions in each other's capitals High Commissions. Outside the capital a country may have a consulate or consulate-general in other cities headed by a consul or consul-general, with slightly different roles, rights and responsibilities as a head of mission. And in places of questionable diplomatic legitimacy like Taiwan or Palestine, less formal names like 'mission' or 'special relations office' might be adopted.

Embassies can be found in the leafy upmarket districts of the world's capital cities. Look for a building with a flag, a stone wall, a few guards, a serpentine line of visa applicants queing outside and perhaps the odd protest. Quite often, by occupying neo-classical mansions with manicured lawns they are treated as showcases to show their nation's splendor to the host country's citizens, which tends to backfire whenever their foreign aid budget gets audited.

The Vienna Convention on Diplomatic Relations of 1961 identifies the special nature of diplomatic missions in some of its articles :

  • Article 20: an embassy may freely display its flag.
  • Article 21: the receiving state will provide suitable premises for an embassy.
  • Article 22: an embassy will not be subjected to search, requisition, attachment or execution. Officers from the sending state cannot enter an embassy without the consent of the head of mission. The sending state is also responsible for protecting the security and dignity of a foreign embassy.
  • Article 23: an embassy will be immune from any taxes.
  • Article 45: if diplomatic relations are severed or even if armed conflict arises between the two, the receiving state should still protect the embassy of the sending state.