O
- Old Navy
- Outlandusa
- Oneplus
- Oak & Luna
- Organic Zoo
- Otrium
- Outdoor Look
- Ordnance Survey
- On The Beach
- Olipop
- Outschool
- Origins
- Overclockers
- Oroton US
- One Hanes Place
- Overtons
- Opodo
- Orvis
- Office Shoes
- OneTravel
- Ouandme
- Oak Furniture Land
- Online Check Writer
- Omorovicza
- Old Time Candy
- Oberoi Hotels
- Ole Henriksen
- onsport
- Original Organics
- Oncourt Offcourt
- Olivers
- Oncros
- ONDO
- Ollie Gray
- Overnight Glasses
- Opopop
- Oxfam Online Shop
- Office Stationery
- Oxygen
- Oxygen Boutique