The Commander-in-Chief Fleet (CINCFLEET) was the admiral responsible for the operations of the ships, submarines and aircraft of the British Royal Navy from 1971 until April 2012. The post was subordinate to the First Sea Lord, the professional head of the Naval Service. In its last years, as the Navy shrank, more administrative responsibilities were added.

The Fleet Commander is a senior Royal Navy post, responsible for the operation, resourcing and training of the ships, submarines and aircraft, and personnel, of the Naval Service. The Vice-Admiral incumbent is required to provide ships, submarines and aircraft ready for operations, and is based at Navy Command Headquarters.