The Permanent Secretary of the Admiralty was the permanent secretary at the Admiralty, the department of state in Great Britain and subsequently the United Kingdom responsible for the administration of the Royal Navy.

Although he was not a Lord Commissioner of the Admiralty, he was as a member of the Board, and did attend all meetings.

Appointments became regular from 1756, and the title of the office was established as Second Secretary to the Admiralty on 13 January 1783.

When the Admiralty Department was abolished in 1964 and its functions merged within a new Ministry of Defence the post holder became formally known as the Permanent Under Secretary of State for the Navy.

He was primarily responsible for the interrelationships and office organization of the various departments that serve the Royal Navy.