| Marcus Dinwiddie | |
| Birth Date: | 27 August 1906 |
| Birth Place: | Washington, D. C., United States |
| Death Place: | Oak Ridge, Tennessee, United States |
| Sport: | Sports shooting |
| Show-Medals: | yes |
Marcus William Dinwiddie (August 27, 1906 - March 20, 1951) was an American sport shooter who competed in the 1924 Summer Olympics.[1] In 1924 he won the silver medal 50 metre rifle, standing in the team free rifle competition. He was born in Washington, D.C., and died in Oak Ridge, Tennessee.[2]