John de Witt may refer to: Johan de Witt (1625–1672), Dutch politician who was assassinated John L. DeWitt (1880–1962), U.S. general in World War II who helped initiate the Japanese-American internment John DeWitt (athlete) (1881–1930), American athlete who competed mainly in the hammer throw John H. DeWitt Jr. (1906–1999), American pioneer in radio broadcasting, radar astronomy and photometry John DeWitt (gridiron football) (born 1970), American arena football lineman