Sir Lionel George Archer Cust, also L. G. A. Cust, (6 June 1896 – 22 May 1962) was a British civil servant, art historian, and General Secretary of the Royal Empire Society. He was the son of Sir Lionel Henry Cust.
He was knighted in 1959.
He was a member of the Mandatory Palestine Civil Service from 1920-36. He is best known for authoring the best known summary of the Status quo of Holy Land sites in 1929: .
He was a cousin of Ronald Storrs.