John Thayer may refer to:
Politicians John R. Thayer (1845–1916), member of the United States House of Representatives from Massachusetts John A. Thayer (1857–1917), member of the United States House of Representatives from Massachusetts John Milton Thayer (1820–1906), United States Senator from Nebraska and Civil War general
Others John Thayer (priest) (1755–1815), Boston priest John B. Thayer (1862–1912), American cricketer and businessman who died on the RMS Titanic Jack Thayer (1894–1945), his son, survivor of the Titanic sinking Jack G. Thayer (1922–1995), American radio executive and disc jockey John Thayer (ornithologist) (1862–1949), American amateur ornithologist John M. Thayer (judge), Connecticut Supreme Court judge
See also John Theyer (1597–1673), English royalist lawyer and writer, antiquary and bibliophile Thayer (disambiguation)