Politics and Business magazines
- Ocean Group Plc
- Ocean Spray Cranberries, Inc
- Oceaneering International, Inc
- Octel Communications Corp.
- Octel Messaging
- Ocular Sciences, Inc.
- Odakyu Electric Railway Co., Ltd.
- Odakyu Electric Railway Company Limited
- Odebrecht S.A.
- Odetics Inc.
- ODL, Inc.
- Odwalla, Inc.
- OEC Medical Systems, Inc.
- OENEO S.A.
- OfficeTiger, LLC
- Officine Alfieri Maserati S.p.A.
- Offshore Logistics, Inc.
- Oglebay Norton Company
- Oglethorpe Power Corporation
- Ohbayashi Corporation