| Oaxacan Milk Stout | Warped Wing Brewing Company | American Stout | |
| Oaxen | Supermoon Beer Company | Belgian Pale Ale | 6.0% |
| OB Lager | Oriental Brewery | American Lager | 4.4% |
| OB Premium Pilsner | Oriental Brewery | German Pilsner | 5.2% |
| OB-1 Certified Organic Ale | Snake River Brewing | English Brown Ale | 4.9% |
| OB.LIV.I.OUS | Griffin Claw | Wheatwine | 13.0% |
| Obamagang Inauguration Ale | Brewery Ommegang | American Stout | |
| Obamanator Maibock | Wynkoop Brewing | Maibock | |
| Obedience | Seedy Brewing | Saison | 8.8% |
| Obeisance | Von Ebert | | |
| Obelus | Transient Artisan Ales | | |
| Obergärig / Münster Alt | Brauerei und Altbierkche Pinkus Mller | American Brown Ale | |
| Oberly's Barrel Aged Irish Coffee Stout | Riverlands Brewing Company | American Imperial Stout | 12.0% |
| Oberon | Bell's Brewery, Inc. | American Pale Wheat Beer | 5.8% |
| Oberon Eclypse | Bell's Brewery, Inc. | | |