| Oil Man | Elevation Beer Co. | American Imperial Stout | 11.0% |
| Oil Man | Elevator Brewing Company | American Imperial Stout | 10.8% |
| Oil of Aphrodite | Jackie O's Pub & Brewery | American Imperial Stout | 10.0% |
| Oil of Aphrodite - Rum Barrel Aged | Jackie O's Pub & Brewery | American Imperial Stout | 10.0% |
| Oil Rigger Stout | HopCat | Russian Imperial Stout | 10.5% |
| Ojos Negros | Rivertown Brewing Company | Fruit Lambic | 6.5% |
| OK-Si | Prairie Artisan Ales | Russian Imperial Stout | 12.0% |
| Oki Doki IPA | ALL IN Brewing & Brouwerij de Molen | American IPA | 6.9% |
| Okie | Prairie Artisan Ales | American Strong Ale | 13.0% |
| Okie Matilde | Prairie Artisan Ales | Saison | |
| Okocim Porter | Browar Okocim | American Porter | 8.3% |
| Okto Festival Ale | Widmer Brothers Brewing | Altbier | 5.3% |
| Oktober Fest - Märzen | Brauerei Aying Franz Inselkammer KG | Märzen | |
| Oktober Fest-Marzen | Ayinger | Märzen | 5.8% |
| Oktoberdunkel | Dugges Ale- & Porterbryggeri AB | European Dark Lager | 6.0% |