| OSB Premium Ale | Tomos Watkin and Sons Ltd. | | 4.5% |
| Oscar Aged In Blackberry Whiskey Barrels | New Belgium Brewing | Wild Ale | 8.8% |
| Oscar Aged in Blackberry Whiskey Barrels | 2017 | New Belgium Brewing | Wild Ale | 8.8% |
| Oscar Blond | Brouwerij Eutropius | Belgian Blonde Ale | 6.6% |
| Oscar Bruin | Brouwerij Eutropius | | 6.5% |
| Oscar's Chocolate Oatmeal Stout | Sand Creek Brewing Company | Oatmeal Stout | 5.6% |
| Oscar's Double Chocolate Milk Stout | Sand Creek Brewing Company | American Imperial Stout | 10.0% |
| Oscars | Sand Creek Brewing Company | Oatmeal Stout | 4.5% |
| Oscillate Wildly | Strangeways Brewing | Wild Ale | 10.0% |
| Oscillation | Brasserie du Bas-Canada | American Barleywine | 11.9% |
| Oscuro Org | Commonwealth Brewing Co. | | |
| Oseka | The Garden Brewery | New England IPA | 6.2% |
| Osiris | 3rd Sign Brewery | American Imperial Stout | 9.0% |
| Osiris | Sun King Brewing Company | American Pale Ale | 5.6% |
| Osiris-Rex | Black Project Spontaneous & Wild Ales | | 9.0% |