An ambassador, rarely embassador, is a diplomatic official accredited to a foreign sovereign or government, or to an international organization, to serve as the official representative of his or her own. In everyday usage it applies to the ranking plenipotentiary minister stationed in a foreign capital. Diplomatic officers heading missions outside the capital, or heads of "interest group" missions between two states which do not have diplomatic relations, are known as consuls. The host country typically allows the ambassador control of specific territory called an embassy, whose territory, staff, and even vehicles are generally afforded diplomatic immunity to most laws of the host country.

The senior diplomatic officers among members of the Commonwealth of Nations are known as High Commissioners, who are the heads of High Commissions. Representatives of the Holy See are known as Papal or Apostolic Nuncios, while the head of a Libyan People's Bureau is a Secretary.

Historically, officials representing their countries abroad were termed ministers, but this term was also applied to diplomats of the second rank. The Congress of Vienna of 1815 formalized the system of diplomatic rank under international law:

Ambassadors are ministers of the highest rank, with plenipotentiary authority to represent their head of state. An Ordinary Ambassador is one heading a permanent diplomatic mission, for instance the senior professional diplomat in an embassy. An Extraordinary Ambassador could be appointed for special purposes or for an indefinite term; politically appointed ambassadors would fall under this category.

Moreover, a Resident Ambassador is one who resides within the country to which s/he is accredited. A Non-Resident Ambassador is one who does not reside within the country to which s/he is accredited, but lives in a nearby country. Thus a resident ambassador to a country might at the same time also be a non-resident ambassador to several other countries.

Among European powers, the ambassador extraordinary and plenipotentiary (French ambassadeur extraordinaire et plénipotentiaire or German ausserordentlicher und bevollmächtigter Botschafter) was deemed the personal representative of the sovereign, and the custom of dispatching ambassadors to the head of state rather than the government has persisted. For example, ambassadors to and from the United Kingdom are accredited to or from the Royal Court of St James, rather than to the State.

Because members of the Commonwealth of Nations have or had a common head of state, they do not exchange ambassadors, but instead have High Commissioners which represent the government rather than the head of state.

Ranking below full ambassador are the rank of envoy, minister resident and chargé d'affaires. They represent their government rather than their head of state. For further details, see diplomatic rank.

Lists of ambassadors

• List of ambassadors
• List of Ambassadors to Canada
• List of Ambassadors and High Commissioners to the United Kingdom
• Ambassadors from Israel
• Ambassadors from the United States

See also

• Diplomatic rank
• Consulate general
• High Commissioner
• Nuncio