William Arnold may refer to: William Arnold (settler) (1587–1676), one of founding settlers in Rhode Island William Arnold (architect) (fl. 1595–1637), master mason in Somerset, England William W. Arnold (1877–1957), U.S. Representative from Illinois William Carlile Arnold (1851–1906), Republican member of the U.S. House of Representatives from Pennsylvania William Richard Arnold (rugby player) (1881–1957), Welsh rugby international William Richard Arnold (bishop) (1881–1965), U.S. Army Chief of Chaplains William Arnold (footballer) (1900–1977), English footballer William Munnings Arnold (1819–1875), Australian member of the New South Wales Legislative Assembly William Delafield Arnold (1828–1859), British author and colonial administrator William Howard Arnold (1901–1976), U.S. Army general William Howard Arnold (physicist), American nuclear physicist William Thomas Arnold (1852–1904), English writer and journalist