Under Secretary of State (U/S) is a title used by senior officials of the United States Department of State who rank above the Assistant Secretaries and below the Deputy Secretary.

Assistant Secretary of State (A/S) is a title used for many executive positions in the United States Department of State, ranking below the under secretaries. A set of six assistant secretaries reporting to the under secretary for political affairs manage diplomatic missions within their designated geographic regions, plus one assistant secretary dealing with international organizations and one equivalent as the coordinator/ambassador at large for counterterrorism. Assistant secretaries usually manage individual bureaus of the Department of State. When the manager of a bureau or another agency holds a title other than assistant secretary, such as "director", it can be said to be of "assistant secretary equivalent rank". Assistant secretaries typically have a set of deputies, referred to as deputy assistant secretaries (DAS).