Marshall Clinton Formby, Jr. (April 12, 1911–December 27, 1984), was a Texas attorney, newspaper publisher, radio executive, and a Democratic politician who served a term in the Texas State Senate from District 30 from 1941 to 1945. He was a defender of West Texas interests and entitled a 1962 book, These Are My People. Formby was a maternal uncle of current Republican State Senator Robert L. Duncan, an attorney from Lubbock who formerly held the District 28 seat until he became chancellor of the Texas Tech University System.