Companies catalogue
- O'Donel High School, Mount Pearl
- O'Leary Sean Dr, St. John's
- O'Neill Foundation Inc, St. John's
- O.V.A.G., Carbonear
- OZ-FM, St. John's
- Oak Ridge Woodworking, Fenwick
- Ocean Choice International, St. John's
- Ocean Science Centre, Logy Bay-Middle Cove-Outer Cove
- Octagon Medical Centre, Paradise
- Octagon Pond Elementary School, Paradise
- Office Chief Information Ofc, St. John's
- Office Fresh Cleaning Svc, Guelph
- Office of the Chief Information Officer, St. John's
- Offshore Safety and Survival Centre (OSSC), Conception Bay South
- Ohara Consulting: Japanese Language & Culture, St. John's
- Ohson Kamal Dr, St. John's
- Old Town Pizza, Mount Pearl
- Oldschool Promotions, Guelph
- Oliver's, St. John's
- On The Rocks Studio, Flatrock
- Once Upon A Child, Burlington
- Once Upon A Child, Brampton
- Once Upon A Child, Hamilton
- Once Upon A Child, Milton
- One Ocean Marine Institute, St. John's
- One Percent Realty, St. John's
- One Stop Laundry, Guelph
- One Tooth Activewear Guelph, Guelph
- Ontario Pharma Research Chemicals, Guelph
- Ooh La La Designs, Pelham
- Oppidan, St. John's
- Optical in Dominion, Mount Pearl
- Optical in Dominion, St. John's
- Optical in Dominion, St. John's
- Optimum Home Inspection Inc, St. John's
- Orange Lodge #26, Cupids
- Orangeville Alterations Sewing and Custom Design, Orangeville
- Organic Tees Canada, Mississauga
- Organizing Pros, Mount Pearl
- Original Footwear Co., Morristown
- Otterbury Hollow, Paradise
- Our Dressing Room, Guelph
- Our Lady, Star of the Sea Catholic Church, Witless Bay
- Our Sock Shoppe, Guelph
- Outport Restaurant & Pub, Paradise
- Outports, Mount Pearl
- Outpost, Guelph
- Oxfam Canada, St. John's
- O’Reilly’s, St. John's