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 , American college football player and Olympic hammer thrower
• John H. DeWitt Jr., American pioneer in radio broadcasting, radar astronomy and photometry
• John DeWitt , American arena football lineman
• John DeWitt, pseudonymous author of some of the Anti-Federalist Papers