Marvin Kirkland Cox (born August 17, 1957) is an American retired politician and educator. A Republican and a former high school teacher, he served in the Virginia House of Delegates from 1990 to 2022, representing the 66th District. From 2018 to 2020, he served as the 55th Speaker of the House of Delegates. Cox served as House Majority Leader from 2010 to 2018 and House Majority Whip from 2004 to 2010.