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 and is accountable to the United States Congress and the Supreme Court. 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, and is accountable to the president.

The United States Capitol Complex is a group of twenty buildings, grounds, and facilities in Washington, D.C., that are used by the United States Congress, and Federal courts. The buildings and grounds within the complex are managed and supervised by the Architect of the Capitol.