- Opaque BR
- Opard Global
- Open Blue Insurance
- Open Box2 BR
- Opencare
- openenglish.com
- openenglish.com.br
- Openfit
- openhagen.com
- Opening Ceremony
- OPI
- Opian
- oplan office affiliates
- opmcpa.go2affise.com
- Opodo
- Opodo DE
- Oppo Campaign IT
- oppo.com
- Opposuits
- OPS! IT
- Optarise DE
- Opte (US)
- OptiBac Probiotics
- Optibiotix
- Optical Center FR
- optic-city.ru
- Optifast DE
- Optifast UK
- OptimallyMe
- Optimal Print AU
- Optimal Print CA
- Optimalprint CH
- Optimal Print UK
- Optimal Print US
- Optimum Nutrition UK
- Optimum Outfit
- OptiWize Health US Program
- Opulent Jewelers
- OPUS Fashion DE
- OPUS Fashion NL
- OQVestir
- OQVestir BR
- OralB NL
- Orange Onions
- Orbisana DE
- Orbit Baby Europe
- Orbitz
- orby.ru
- Orchard Mile
- Orchideen Klusmann DE