William Arnold

William Arnold may refer to:

Military

 * William Richard Arnold (bishop) (1881–1965), U.S. Army Chief of Chaplains
 * William Howard Arnold (general) (1901–1976), U.S. Army general

Politicians

 * William Munnings Arnold (1819–1875), politician and speaker of the New South Wales Legislative Assembly
 * William Carlile Arnold (1851–1906), U.S. Representative from Pennsylvania
 * William W. Arnold (1877–1957), U.S. Representative from Illinois
 * William Arnold (bailiff) (1903–1973), Bailiff of Guernsey

Sports

 * William Arnold (footballer) (1900–1977), English footballer
 * Willie Arnold (1881–1957), Welsh rugby international player

Others

 * William Arnold (settler) (1587–1676), founding settler in Rhode Island
 * William Arnold (architect) (fl. 1595–1637), master mason in Somerset, England
 * William Delafield Arnold (1828–1859), British author and colonial administrator
 * William W. Arnold (ornithologist) (1843–1923), American physician and ornithologist
 * William Thomas Arnold (1852–1904), English writer and journalist
 * William Howard Arnold (physicist) (fl. 1955–2004), American nuclear physicist