| Oil of Gladness | Three Floyds / Dark Horse | American Barleywine | 11.0% |
| Oil Piers Gingerbread Spiced Porter | Surf Brewery | American Porter | 6.5% |
| Oil Rig | Ritual Brewing Co | Imperial IPA | 7.0% |
| Oil Rigger Stout | HopCat | Russian Imperial Stout | 10.5% |
| Oil Spill | To Øl | New England IPA | 10.5% |
| Oinj | Freak Folk Bier | Wild Ale | 7.0% |
| The Oister | De Garde Brewing | Wild Ale | 5.5% |
| OJ Run | Narrow Gauge Brewing Company | Imperial IPA | 8.6% |
| Ojos Negros | Rivertown Brewing Company | Fruit Lambic | 6.5% |
| Ojuice | Three Magnets Brewery | Imperial IPA | 8.2% |
| OK Brewer | Triptych Brewing | American IPA | 6.3% |
| OK, Boomer | Brouwerij Frontaal | English IPA | 8.5% |
| OK-Si | Prairie Artisan Ales | Russian Imperial Stout | 12.0% |
| Ok2berfest | Two Roads Brewing Co. | Märzen | 5.8% |
| Oki Doki IPA | ALL IN Brewing & Brouwerij de Molen | American IPA | 6.9% |