William Napier
William Napier is the name of the following people:
- William Napier, 9th Lord Napier (1786–1834), British naval officer, politician and diplomat
- William Napier (General) (1818–1903), British general
- William Napier (Admiral) (1877–1951), British admiral
- William Napier, 13th Lord Napier (1900–1954), Scottish nobleman, politician and military man
- William Napier , pseudonym of Christopher Hart (* 1965), British writer
- William Ewart Napier (1881–1952), American chess player of British origin
- William Francis Patrick Napier (1785–1860), British lieutenant general and military historian
- William M. Napier (* 1940), British astronomer and author, see Bill Napier