| Occupied Space | Highland Park Brewery | Wild Ale | 5.8% |
| Ocho De Mayo | Short's Brewing Company | Gose | 4.0% |
| OCP (Oatmeal Creme Pie) | Pigeon Hill Brewing Company | American Brown Ale | 6.0% |
| Octoberfest | Abita Brewing Company | Märzen | 5.4% |
| Octoberfest | Samuel Adams | Märzen | 5.3% |
| Octoberfest | Trap Rock Restaurant and Brewery | Märzen | |
| Octoberfest (discontinued) | Gottberg Brew Pub | Märzen | |
| Octoberfest Beer | Bell's Brewery, Inc. | Märzen | 5.5% |
| Octoberfest Lager | Central Waters Brewing Company | Märzen | 5.5% |
| Octoberfest Maerzen | Old Dominion Brewing Co. | Märzen | 5.9% |
| Ocularity | Bottle Logic | Imperial IPA | 9.5% |
| Oculus | Crooked Stave Artisan Beer Project | Wild Ale | 9.0% |
| Odd Brewin' | Outer Banks | Flanders Oud Bruin | 7.5% |
| Oddland Ginger Berry Brown Ale | Elysian Brewing Co. | American Brown Ale | 8.0% |
| Oddland Peppercorn Saison | Elysian Brewing Co. | Saison | 7.0% |