William Blades (December 5, 1824 - April 27, 1890), English printer and bibliographer, was born at Clapham, London.

In 1840 he was apprenticed to his father's printing business in London, being subsequently taken into partnership. The firm was afterwards known as Blades, East & Blades. His interest in printing led him to make a study of the volumes produced by Caxton's press, and of the early history of printing in England.

His Life and Typography of William Caxton, England's First Printer, was published in 1861-1863, and the conclusions which he set forth were arrived at by a careful examination of types in the early books, each class of type being traced from its first use to the time when, spoilt by wear, it passed out of Caxton's hands. Some 450 volumes from the Caxton Press were thus carefully compared and classified in chronological order.

In 1877 Blades took an active part in organizing the Caxton celebration, and strongly supported the foundation of the Library Association . He was a keen collector of old books, prints and medals. His publications relate chiefly to the early history of printing, the Enemies of Books, his most popular work, being produced in 1881. He died at Sutton in Surrey on April 27 1890.