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. He was head of the Admiralty Secretariat, later known as the Department of the Permanent Secretary. Although he was not a Lord Commissioner of the Admiralty, he was as a member of the Board, and did attend all meetings. The post existed from 1702 to 1964.

The Admiralty was a department of the Government of the United Kingdom responsible for the command of the Royal Navy until 1964, historically under its titular head, the Lord High Admiral – one of the Great Officers of State. For much of its history, from the early 18th century until its abolition, the role of the Lord High Admiral was almost invariably put "in commission" and exercised by the Lords Commissioner of the Admiralty, who sat on the governing Board of Admiralty, rather than by a single person. The Admiralty was replaced by the Admiralty Board in 1964, as part of the reforms that created the Ministry of Defence and its Navy Department.