James Paul Chapin (1889–1964) was an American ornithologist.
Chapin is one of the highest-regarded ornithologists of the twentieth century. He was joint leader (with Herbert Lang) of the Lang–Chapin expedition, which made a biological survey of the Belgian Congo between 1909 and 1915. For his work The Birds of the Belgian Congo, Part I, he was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences in 1932. He received a doctorate from Columbia University in 1919, and then began a lengthy career at the American Museum of Natural History.
Chapin served as the 17th president of The Explorers Club from 1949 to 1950.