| Ope! Brewing Co. | West Allis, Wisconsin |
| Open Water Brewery | Knutsboda, Finland |
| Ophiussa Brewing Company | Setúbal, Portugal |
| Opperbacco | Italy |
| Oppigårds Bryggeri | Hedemora, Sweden |
| Oppigårds Bryggeri/Närke Kulturbryggeri | |
| Oproer Brouwerij | Utrecht, Netherlands |
| Oracle Brewing Company | Saginaw, MI |
| Orange Belt Brewing | Gulfport, FL |
| Orange Blossom Brewing Company | Orlando, Florida |
| Orange Blossom Pilsner | |
| Orange County Brewing @ Brown Barn Farms | New Hampton, New York |
| Oranjeboom Bierbrouwerij B. V. | |
| Orbital Brewing | Andrézieux-Bouthéon, France |
| Orca brau | Nürnberg, Germany |