William Andleby (Anlaby) (executed at York, 4 July 1597) was an English Roman Catholic priest. He is a Catholic martyr, beatified in 1929.
He was born at Etton in Yorkshire of a well-known gentle family. At 25 he went abroad to take part in the Dutch war. He visited Douay College to interview William Allen; a discussion led to his conversion, and eventually Andleby became a Catholic priest.
He is known to have taken his ministry to Mr. Tyrwhitt's, in Lincolnshire, and also to the Catholic prisoners in Kingston upon Hull's blockhouse.
After about 20 years, he was condemned for his priestly character, and executed with three laymen, John Abbot, Thomas Warcop, and Edward Fulthrop.