Sir William Geraghty, KCB (1917 – 7 May 1977) was a British civil servant.
Educated at Brasenose College, Oxford, he entered the civil service in 1939, joining the War Office.
He then served in the Cabinet Office, before promotion to deputy secretary.
He was Second Permanent Secretary at the Ministry of Defence with responsibility for administration from 1975 to 1976.
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