Marvin Tandy Culpepper, Sr. (November 26, 1908 – January 31, 1970), was an engineer, machinist, and farmer from Jackson Parish in North Louisiana, who served from 1964 to 1968 as a Democrat in the Louisiana House of Representatives. His one term in office coincided with the first term of Governor John McKeithen. He was defeated for reelection by his fellow Democrat , who in his second term in the chamber became the House Speaker.