| Oggi's Pizza and Brewing - Vista | Vista, California |
| Ohio Brewing | Niles, Ohio |
| Ohza | |
| Okanagan Spring Brewery | Vernon, Canada |
| OL Beer | São José dos Pinhais, Brazil |
| Ola Brew Company | Kailua-Kona, HI |
| Old Bakery Beer Company | Alton, Illinois |
| Old Chimney's Brewery | United Kingdom |
| Old City Brewing | Austin, Texas |
| Old Dominion Brewing Co. | Dover, Delaware |
| Old Hat Brewery | Lawton, Michigan |
| Old Irving Brewing Co. | Chicago, Illinois |
| Old Klaverack Brewery | Hudson, New York |
| Old Nation Brewing Company | Williamston, Mi |
| Old Orange Brewing Co. | Orange, Ca. |