| Marvin Lewellyn | |
| Birth Date: | 11 February 1919 |
| Birth Place: | Chariton, Iowa, U.S. |
| Death Place: | North Mankato, Minnesota, U.S. |
| Alma Mater: | Northern Iowa (1941) Iowa (1949) |
| Coach Years1: | 1947–1951 |
| Coach Team1: | South Dakota Mines |
| Coach Years2: | 1952–1957 |
| Coach Team2: | Wayne State (NE) |
| Overall Record: | 42–44–8 |
| Championships: | 2 SDIC (1947, 1951) |
Marvin "Barney" Lewellyn (February 11, 1919 – August 28, 2010) was an American football coach.[1] He served as the head football coach at the South Dakota School of Mines in Rapid City, South Dakota from 1947 to 1951.[2] He moved to Wayne, Nebraska to become the head football coach at Wayne State College from 1952 to 1957.[3]