Oliver S. Crosby | |
|---|---|
 US Ambassador Oliver S. Crosby and President Ahmed Sekou Toure in 1978 | |
| US Ambassador to Guinea | |
| In office October 27, 1977 – August 1, 1980 | |
| President | Jimmy Carter |
| Preceded by | William C. Harrop |
| Succeeded by | Allen C. Davis |
Oliver Sexsmith "Mike" Crosby (April 27, 1920 to October 25, 2014) was an American diplomat who served as United States Ambassador to Guinea. He was the son of the classicist Henry Lamar Crosby.