Companies catalogue
- O D S Commercial Printing, Sarnia
- O'tools Rent or Buy, Forest
- Oakville Ford Kids & Co Daycare, Richmond Hill
- Oakville Home Daycare, Oakville
- Oakville Parent Child, Oakville
- Oakville Trafalgar | YMCA Child Care, Oakville
- Oasis, Point Edward
- Obsolete Automotive, Point Edward
- Ogie's Lift Truck Service Ltd, Chatham-Kent
- Ogilvie Electric Inc, Sarnia
- Oil Gard Sarnia, Sarnia
- Oil Springs Post Office, Oil Springs
- Okhee's Corner Store, Oakville
- Ol'Reids Smoke Shop, Sarnia
- Ola Bakery & Pastry, Hamilton
- Om On Locke, Hamilton
- On Edge Fitness, Sarnia
- On The Go Convenience & Cell Phones, Burlington
- On the Run, Hamilton
- On the Run, Hamilton
- On the Run, Hamilton
- On the Run, Burlington
- On the Run, Burlington
- On the Run, Hamilton
- On the Run, Burlington
- On the Run, Hamilton
- On the Run, Burlington
- On the Run, Burlington
- On the Run, Oakville
- On the Run, Oakville
- On the Run, Oakville
- On the Run, Oakville
- On the Run, Oakville
- One Stop Automotive, Sarnia
- One Tooth Sarnia, Sarnia
- Ontario Convenience, Sarnia
- Ontario Early Years Centre, Hamilton
- Ontario Hose Specialities, Corunna
- Ontario Lottery Corporation, Sarnia
- Onyx Salon & Spa, Sarnia
- Orkin Pest & Termite Control, Port Huron
- Ortech Environmental Inc, Sarnia
- OshKosh B'gosh, Guelph
- OshKosh B'gosh, Sarnia
- Ottawa Textiles, Hamilton
- Our Kids Child Care-Kate's Kids, Sarnia
- Our Lady of Fatima YMCA Child Care Centre, Grimsby
- Our Lady of Mount Carmel, Hamilton
- Our Lady of Peace | YMCA Child Care/Before and After School programs, Oakville