William Brewster (July 5, 1851 – July 11, 1919) was an American ornithologist.[1] He was the curator of birds at the Museum of Comparative Zoology at Harvard University from 1885 until his death.[1] He was the co-founder, with Elliott Coues and Joel Asaph Allen, of the American Ornithologists' Union in 1883.[2] He wrote Birds of the Cape Regions of Lower California (1902) and Birds of the Cambridge Region of Massachusetts (1906).