Mark Marnell (1926 - 9 July 1992) was an Irish hurler who played as a left corner-back for the Kilkenny senior team.
Born in Oldtown, Danesfort, County Kilkenny, Marnell first arrived on the inter-county scene when he first linked up with the Kilkenny senior team, making his debut in the 1947 championship. Marnell was a regular member of the team over the next few years. During that time he won one All-Ireland medal and three Leinster medals. He was an All-Ireland runner-up on one occasion.
Marnell also represented the Leinster inter-provincial team, however, he never won a Railway Cup medal. At club level he won one championship medal with Tullaroan.