| Otsuchi Old Stock Ale 2012 | North Coast Brewing Co. | Old Ale | 11.7% |
| Ottakringer Helles | Ottakringer Brauerei AG | | 5.1% |
| Otter Creek Imperial India Pale Ale | Otter Creek Brewing & Wolaver's Organic Ales | Imperial IPA | 11.0% |
| Otter Creek Russian Imperial Stout | Otter Creek Brewing | Russian Imperial Stout | 10.0% |
| Otter Creek Russian Imperial Stout | Otter Creek Brewing & Wolaver's Organic Ales | American Imperial Stout | 10.6% |
| Otto | Hair of the Dog Brewing Company | | |
| Otto Ale | Victory Brewing | Smoked Beer | 8.1% |
| Otto From The Wood | Hair of the Dog Brewing Company | American Strong Ale | 13.0% |
| Otto In Oak | Victory Brewing | Smoked Beer | |
| Otto's Hefeweizen | Otto's Pub and Brewery | Hefeweizen | 7.1% |
| Otto's Weizenbock | Otto's Pub and Brewery | Weizenbock | 7.2% |
| Oubliant | Forest & Main | Tripel | 10.0% |
| Oubliette | Seventh Son Brewing Co | Russian Imperial Stout | 12.0% |
| Oud 15 | Bullfrog Brewery | Flanders Red Ale | 13.0% |
| Oud Beersel Bersalis Tripel | Brouwerij Oud Beersel | Tripel | 9.5% |