John Todd or Tod may refer to:

Clergy

• John Todd (abolitionist) (1818–1894), preacher and 'conductor' on the Underground Railroad
• John Todd (author) (1800–1873), American minister and author
• John Todd (bishop), Anglican bishop in the early 17th century
• John Baptist Todd (1921–2017), Pakistani Franciscan priest

Mathematics, science, and medicine

• John Todd (British biologist) (born 1958), British biologist working on diabetes mellitus
• John Todd (Canadian biologist) (born 1939), Canadian biologist working in the field of ecological design
• John (Jack) Todd (1911–2007), Northern Irish and American mathematician working in the field of numerical analysis
• J. A. Todd (John Arthur Todd, 1908–1994), English mathematician
• John Lancelot Todd (1876–1949), Canadian physician and parasitologist
• John W. Todd (1912–1989), British physician and author

Politics and government

• John Tod (1779–1830), American judge and politician
• John Todd (politician) (fl. 1991–1999), Canadian politician from the Northwest Territories
• John Todd (Virginia soldier) (1750–1782), early Virginia official, Kentucky soldier, and great-uncle of Mary Todd Lincoln
• John Blair Smith Todd (1814–1872), delegate to US Congress from Dakota Territory
• John J. Todd (born 1927), Justice of the Minnesota Supreme Court
• John Rawling Todd (1929–2002), British colonial civil servant

Sports

• John Kennedy Tod (1852–1925), Scottish rugby union player
• John Todd (footballer) (born 1938), Australian rules football player and coach
• John Todd (rugby league), rugby league footballer of the 1910s and 1920s

Other

• John Todd (actor) (1876–1957), American actor who played Tonto on the Lone Ranger radio series
• John Todd (businessman) (1927–2015), New Zealand businessman
• John Todd (conspiracy theorist) (1949–2007), source for fundamentalist Baptist author Jack Chick
• John Todd (RAF officer) (1899–1980), British World War I flying ace
• John Payne Todd (1792–1852), step-son of U.S. President James Madison