The Architect of the Capitol (AOC) is the federal agency responsible for the maintenance, operation, development, and preservation of the United States Capitol Complex. It is an agency of the legislative branch of the federal government^[1] and is accountable to the United States Congress and the Supreme Court.^[2] Both the agency and the head of the agency are called "Architect of the Capitol". The head of the agency is appointed to a 10-year term by the president of the United States, confirmed by the United States Senate,^[3] and is accountable to the president.^[4]

The agency had 2,444 employees and an annual budget of approximately $788 million as of September 2022.^[5]

The head of the agency sits on the Capitol Police Board, which has jurisdiction over the United States Capitol Police, and on the United States Capitol Guide Board, which has jurisdiction over the United States Capitol Guide Service.

Until 1989, the architect of the Capitol was appointed by the president of the United States for an indefinite term. Legislation in 1989 provides that the president appoints the architect for a term of ten years, with the advice and consent of the Senate, from a list of three candidates recommended by a congressional commission composed of the speaker of the House, president pro tem of the Senate, the majority and minority leaders of the House and Senate, and the chair and ranking members of the House Committee on House Administration, the Senate Committee on Rules and Administration, and the House and Senate Committees on Appropriations.^[6] On confirmation by the Senate, the architect becomes an official of the legislative branch as an officer and agent of Congress.^{[citation needed]} The architect is eligible for reappointment after completion of the term.

The Architect of the Capitol is responsible to Congress and the Supreme Court for the maintenance, operation, development, and preservation of 17.4 million square feet (1,620,000 m²; 400 acres; 162 ha) of buildings and more than 553 acres (224 ha) of land throughout Capitol Hill.^[2]

The office is also responsible for the upkeep and improvement of the Capitol grounds, and the arrangement of inaugural ceremonies and other ceremonies held in the building or on the grounds. Legislation over the years has placed additional buildings and grounds under the Architect of the Capitol.^{[citation needed]}

The Capitol Complex includes:^[2]

• the Capitol
• Capitol Visitor Center
• the eight congressional office buildings
  • Cannon
  • Ford
  • Longworth
  • O'Neill
  • Rayburn
  • Russell
  • Dirksen
  • Hart
• Library of Congress buildings
• United States Supreme Court Building
• United States Botanic Garden
• Thurgood Marshall Federal Judiciary Building
• Capitol Power Plant
• Juno Webster Senate Page Residence
• United States Capitol Police headquarters and K9 division facilities
• other facilities

• Office of the Supervising Architect for the U.S. Treasury
• Architecture of Washington, D.C.