John Langdon may refer to:
John Langdon (bishop) (died 1434), English Bishop of Rochester John Langdon (driver) (born 1947), New Zealand harness race driver John Langdon (historian) (1944–2016), Canadian historian John Langdon (politician) (1741–1819), American politician from New Hampshire John Langdon (typographer) (1946–2026), American typographer known for his ambigrams
See also John Langdon Down (1828–96), British physician