| Old Marcus Ale | Middle Ages Brewing | Extra Special / Strong Bitter (ESB) | 6.6% |
| Old Market Stout | Upstream Brewing Old Market | American Stout | |
| Old Marley Barleywine | Thomas Hooker Brewing | American Barleywine | 10.0% |
| Old Mephisto | Bryggeriet Djaevlebryg | English Barleywine | 12.0% |
| Old Mill Pond ESB | The Cambridge House | Extra Special / Strong Bitter (ESB) | 6.5% |
| Old Milwaukee | Pabst Brewing Company | American Lager | 4.6% |
| Old Monk 10000 Super Beer | Mohan Breweries and Distilleries, LTD | | |
| Old Monk's Ale | De Struise Brouwers | Quadrupel (Quad) | 10.0% |
| Old Mose | Martin House Brewing Company | | 13.3% |
| Old Nebby | East End Brewing Company | Old Ale | 6.9% |
| Old Neighborhood Oatmeal Porter | Mother Earth Brewing | American Porter | 5.5% |
| Old Nick | Wells and (&) Youngs Brewing Company Ltd. | English Barleywine | 7.2% |
| Old Nick | Youngs & Company Brewery | | 7.2% |
| Old Nick Pale Ale | Richbrau Brewing Company | American Pale Ale | 5.5% |
| Old No. 1 | Scuttlebutt Brewing | | 12.9% |