O
- Office Depot
- Ollie Gray
- Our Pet WareHouse
- Old Navy
- Orchira
- Online4baby
- Office Shoes
- Overclockers
- O2
- Omaha Steaks
- Origins
- Omio
- Origins UK
- Oasis UK
- Old Navy Canada
- Orvis
- OnBuy
- Orvis UK
- Opodo
- Oliver Bonas
- Online Fabric Store
- Ordnance Survey
- OshKosh B'gosh
- OnlineGolf
- OTAA
- One Hanes Place
- Overnight Prints
- Origin PC
- Onnit
- Overtons
- OTTY
- Oak Furniture Superstore
- Oxford Online Pharmacy
- Oxygen
- OKA
- OZ Game Shop
- Oroton
- Outdoor Look
- On The Beach
- Oneplus