| Brewery | Location |
|---|---|
| Olde Peninsula Brewpub and Restaurant | Kalamazoo, Michigan |
| Oldenberg Brewery | Fort Mitchell, Kentucky |
| Oliphant | Somerset |
| Oliver Ales | |
| Olivers Cider & Perry | United Kingdom |
| Ology Brewing | |
| Olvalde Farm & Brewing Company | Rollingstone, Minnesota |
| Olvi | IISALMI, Finland |
| Ölvisholt Brugghús | Iceland |
| Omer Vander Ghinste | Bellegem, Belgium |
| Omni Brewing Co. | Maple Grove |
| Omnipollo | Stockholm, Sweden |
| Omnipollo & Buxton Brewery | |
| Omnipollo / 3 Sons | |
| Omnipollo / Dugges | Sweden |