John S. Smith may refer to:
John Shuter Smith (died 1871), Canadian lawyer John Sidney Smith (legal writer) (1804–1871), English legal writer John Sidney Smith (rugby union) (1860–?), English rugby union forward John Speed Smith (1792–1854), American politician John Stafford Smith (1750–1836), British composer John Samuel Smith (1841–1882), New South Wales politician John Spencer Smith (1769–1845), British diplomat, politician and writer John Smalman Smith, British judge in the Colony of Lagos