Bragg was elected Fellow of the Royal Society in 1907, vice-president in 1920, and served as President of the Royal Society from 1935 to 1940. He was elected an International Member of the United States National Academy of Sciences in 1939 and an International Member of the American Philosophical Society. He was elected as a member of the Royal Academy of Science, Letters and Fine Arts of Belgium on 1 June 1946.