Sir Douglas William Gretton Wass (15 April 1923 – 4 January 2017) was a British civil servant. He served as Permanent Secretary to HM Treasury from 1974 to 1983. Wass was Permanent Secretary to HM Treasury from 1974 to 1983 and served as joint head of the civil service in 1981.
He was appointed a Companion of the Order of the Bath (CB) in 1971, elevated to Knight Commander (KCB) in 1975 and further elevated to Knight Grand Cross (GCB) in 1980. In 1985, he was awarded an Honorary Degree (Doctor of Letters) by the University of Bath.
Wass died on 4 January 2017 in London at the age of 93.