The Chief of Naval Operations (CNO) is the senior military officer in the United States Navy. The CNO is an admiral (four-star) and is responsible to the Secretary of the Navy for the command, utilization of resources and operating efficiency of the operating forces of the Navy and of the Navy shore activities assigned by the Secretary. The CNO has administrative, rather than operational command authority over United States naval forces. The operational chain of command runs from the Secretary of Defense directly to the regional commanders, who have command authority over all military forces in their region. This structure in which the service chiefs are responsible for personnel and readiness issues, while the regional commanders are operationally responsible for the command of the military forces is intended to allow the United States military the ability to function as a coherent whole.

A member of the Joint Chiefs of Staff, the CNO is the principal naval advisor to the President of the United States and to the Secretary of the Navy on the conduct of war, and is the principal advisor and naval executive to the Secretary on the conduct of naval activities of the United States Department of the Navy. Assistants are the Vice Chief of Naval Operations (VCNO), the Deputy Chiefs of Naval Operations (DCNOs) and a number of other ranking officers. These officers and their staffs are collectively known as the Office of the Chief of Naval Operations (OpNav).

List of CNOs