John de Witt

• Johan de Witt, Dutch politician who was assassinated
• John L. DeWitt, U.S. general in World War II who helped initiate the Japanese-American internment
• John [DeWitt (athlete)], American college football player and Olympic hammer thrower
• John H. DeWitt [Jr.], American pioneer in radio broadcasting, radar astronomy and photometry
• John DeWitt (gridiron football), American arena football lineman
• John DeWitt, pseudonymous author of some of the Anti-Federalist Papers