William Augustus Brevoort Coolidge (August 28, 1850 - May 8, 1926) was an American historian, theologian and mountaineer.
Coolidge was born in New York City as the son of Frederic William Skinner Coolidge, a Boston merchant, and Elisabeth Neville Brevoort, sister of James Carson Brevoort and Meta Brevoort. He studied history and law at St. Paul's School in Concord, New Hampshire, at Elizabeth College, Guernsey, and at Exeter College, Oxford. In 1875, he became a Fellow of Magdalen College, Oxford. From 1880 to 1881 he was professor of British history at Saint David's College in Lampeter and in 1883 he became a priest of the Anglican church.
In 1870 at the age of twenty he was made a member of the Alpine Club. Coolidge was one of the great figures of the so-called silver age of alpinism, making first ascents of the few significant peaks in the Alps that had not been climbed during the golden age of alpinism. On many of these climbs he was accompanied by his aunt, Meta Brevoort, and a pet dog, Tschingel, given to him by one of his guides, Christian Almer.
In 1885 he moved to Grindelwald, Switzerland, where he died in 1926.