Companies catalogue
- O'Brien Masonry Contractor, London
- O'Neill Academy Of Dance, London
- OES Inc., London
- OK Tire Stores Inc, London
- Oak Park Co-Operative Children Centre Inc, London
- Oakridge Minimart, London
- Oasis Counselling and Consulting Services, London
- Ocean Building Maintenance, London
- Oil Changers, Brantford
- Oil Gard Anti-Rust Canada Ltd, London
- Old River Farm, Glencoe
- Oliver & Associates Van Bart Real Estate Brokerage, London
- Olsen Europe, London
- Olsen Europe, London
- Omega Contractors, London
- Omni Connect, London
- On The Edge, Ingersoll
- Oneida Day Care, Southwold
- Onlinecoffeestore.com, London
- Only, London
- Ontario Ag Equipment, Saint Marys
- Ontario Concrete Repair & Restoration, London
- Ontario Copier, Toronto
- Ontario Door Controls Ltd, London
- Ontario Early Years Centres, London
- Ontario Home Renovators, London
- Ontario Independent Meat Processors, Guelph
- Ontario Tractor Inc, Dorchester
- Open Storage Solutions Inc, London
- Optimum Tax, London
- Orchard Park Nursery School Inc, London
- Organic Works Bakery (Inside Wellington Market Kitchen Restaurant), London
- Orgill Canada, London
- Origins Co., London
- Orr Cleaners, London
- Orr Cleaners, London
- Orr Cleaners, Strathroy
- Oscar Temple & Sons Constr, Saint Thomas
- Ostojic Walter & Sons General Construction Ltd, Saint Thomas
- Our Lady of Mount Carmel School, Dashwood
- Out 'N Back Catering & Takeout, London
- Out ta Site, Hamilton
- Outpost2 by Mac Outpost, London
- Over55 London, London
- Overhead Door Company of London, London
- Oxford Builders Supplies, London
- Oxford Cattle Company, Burgessville
- Oxford Computers, London
- Oxford Concrete Forming Inc., Burgessville