John Robert Zellner (born April 5, 1939) is an American civil rights activist. He graduated from Huntingdon College in 1961 and that year became a member of the Student Nonviolent Coordinating Committee (SNCC) as its first white field secretary. Zellner was involved in numerous civil rights efforts, including nonviolence workshops at Talladega College, protests for integration in Danville, Virginia, and organizing Freedom Schools in Greenwood, Mississippi, in 1964. He also investigated the murders of Chaney, Goodman, and Schwerner that summer.