William Spotswood Green CB (10 September 1847 – 22 April 1919) was an Irish naturalist, specialized on marine biology. Born at Youghal and educated at Trinity College in Dublin, he was ordained a priest in 1873. Already before he left the services of the Church in 1890, he had worked on marine biology. In the 1880s, he participated as a leading member in several research expeditions sponsored by the Royal Irish Academy. In 1892, he became the Inspector of Fisheries. Combined with this work he was a Commissioner on the Congested Districts Board, where his intimate knowledge of human conditions in western Ireland was of great service. In 1914 he shook off the trammels of office, and retired to Westcove House, Caherdaniel, County Kerry. There he died five years later.