| O'Hara's Brewpub and Restaurant | Saint Cloud, Minnesota |
| O'so Brewing Company | |
| O.T. Brewing Company | Calgary, Canada |
| O/O / Stigbergets Bryggeri | Sweden |
| O/O Brewing | Göteborg, Sweden |
| Oak Creek Brewery | Sedona, Arizona |
| Oak Highlands Brewery | Dallas, TX |
| Oaken Barrel Brewing | Greenwood, Indiana |
| Oakham Ales | Peterborough, United Kingdom |
| Oakland Brewing Company | |
| Oakshire Brewing | Eugene, Oregon |
| Oasis Brewery and Restaurant | Boulder, Colorado |
| Oasis Brewery Annex | Boulder, Colorado |
| Oasis Texas Brewing Company | Austin |
| Oast House Brewers | Niagara-on-the-Lake, Canada |