| Title | Author |
|---|---|
| Osborne, John | Wyoming State Archives |
| Ostrom, George, of Sheridan, World War I soldier and artist | Douglas R. Cubbison |
| Outfitting in Wyoming | Brian Beauvais |
| Overland Trail, defense of | Rebecca Hein |
| Overton, Carrie Burton. First African-American Female Student at UW | Kim Viner |
| Oyster Ridge Music Festival | |
| O’Bryan, Lowell, death of on UW campus, 1922 | Phil Roberts |