O
- OPPO Store UK
- Obuy.com
- Old Navy
- OnePlus UK
- Otrium
- Opodo
- Origins
- One Hanes Place
- Origins UK
- Omaha Steaks
- Oasis UK
- Omio
- Orthofeet
- Oral-B
- Orvis
- Orvis UK
- Old Navy Canada
- On The Beach
- Office Shoes
- OnBuy
- O2
- Overclockers
- Overnight Prints
- Oak Furniture Superstore
- Online Fabric Store
- Original Penguin
- OnlineGolf
- Overtons
- OTTY
- Oxford Online Pharmacy
- Oxygen
- OKA
- Onnit
- Oroton
- One World Observatory
- Outdoor Look
- OnePiece UK
- Oneplus
- OshKosh B'gosh
- Ordnance Survey