This is a list of ambassadors of the United States to individual nations of the world, to international organizations, to past nations, and ambassadors-at-large.

Ambassadors are nominated by the President and confirmed by the Senate.

An ambassador can be appointed during a recess of the Senate, but can serve only to the end of the next session of Congress unless subsequently confirmed by the Senate. 

Ambassadors serve "at the pleasure of the President," which means that they can be dismissed at any time.

An ambassador may be a career foreign service officer or a political appointee.

In most cases, U.S. ambassadors who are career foreign service officers serve a tour of approximately three years in a foreign post.

Ambassadors who are political appointees will customarily tender their resignations upon inauguration of a new President.

As embassies fall under the jurisdiction of the Department of State, ambassadors answer to the Secretary of State.

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