William Garden Cowie (8 January 1831 – 26 June 1902) was bishop of the Anglican Diocese of Auckland, New Zealand, from 1870 to 1902. Although he succeeded George Selwyn in having jurisdiction in this portion of New Zealand, he was the first bishop to be known specifically as Bishop of Auckland. His wife Eliza Jane Cowie (1835-1902) was a distinguished religious worker in her own right, and Bishop Cowie's journals refer frequently to her work with him.
He was ordained to the diaconate in 1854 by the Bishop of Ely, and to the priesthood in 1855, also by the Bishop of Ely. He was an important influence on the expansion and development of the Anglican Church in Aotearoa, New Zealand and Polynesia during the long period of his episcopate. He was also closely involved with the ordination of indigenous Melanesian clergy. Cowie attended the Lambeth Conference in 1888 and 1897. He was Primate of the Anglican Church of New Zealand from 1895 to 1902. On 21 June 1902, he died at Wellington, New Zealand.