William Simms may refer to:
- William Simms (instrument maker) (1793–1860), British astronomical instrument maker
- William E. Simms (1822–1898), U.S. Representative and Confederate Senator from Kentucky
- William Gilmore Simms (1806–1870), 19th century American writer
- William Simms, 16th century Irish sailor alleged to have lived at Pikes on Cliffs, Spain