Companies catalogue
- O'Brien's Eatery & Pub, Ottawa
- O'Grady's Outpost, Ottawa
- O'Heaphy's Irish Pub, Kemptville
- OLV Banquet Hall, Ottawa
- Obsession Lounge, Ottawa
- Olde Bytown Bed & Breakfast, Ottawa
- Olde Towne Bakery, Carleton Place
- Olmstead Eric D, Ottawa
- Ontario Berry Growers Association, Kemptville
- Ontario East Wood Centre & Eco-Industrial Park, Kemptville
- Ontario English Catholic Teachers Association Ottawa-Carleton Unit, Ottawa
- Ontario Nurses Association, Ottawa
- Ontario Nurses Association The Ottawa Hospital Local 83, Ottawa
- Ontario Secondary School Teachers Federation, Kemptville
- Options Jazz Lounge at Brookstreet, Ottawa
- Orchard View Wedding & Event Centre, Ottawa
- Orkin Canada, Sudbury
- Orthotics Prosthetics Canada, Ottawa
- Osgoode Bible Chapel, Ottawa
- Ottawa Audiology Services, Ottawa
- Ottawa BMX Association, Ottawa
- Ottawa Ballet School, Ottawa
- Ottawa Best Hotel, Ottawa
- Ottawa Business Park, Ottawa
- Ottawa Champions Baseball Club, Ottawa
- Ottawa Chinese Bible Church, Ottawa
- Ottawa Community Immigrant Services Organization, Ottawa
- Ottawa Construction Association, Ottawa
- Ottawa Dance Academy, Ottawa
- Ottawa Dance Centre Schools, Ottawa
- Ottawa Dance Sport Inc., Ottawa
- Ottawa District Hockey Association, Ottawa
- Ottawa Flying Club, Ottawa
- Ottawa Golf Club - Irish Hills Golf & Country Club, Ottawa
- Ottawa Hot Air Balloon Rides, Ottawa
- Ottawa Hungarian Community Centre, Ottawa
- Ottawa Lions Track & Field Club, Ottawa
- Ottawa Little Theatre Warehouse, Ottawa
- Ottawa Marriott Hotel, Ottawa
- Ottawa Nepean Canadians Sports Club Inc, Ottawa
- Ottawa Parks, sports fields and outdoor recreation, Ottawa
- Ottawa Police Association, Ottawa
- Ottawa Rec Sports, Ottawa
- Ottawa Sport, Ottawa
- Ottawa Tennis & Lawn Bowling Club, Ottawa
- Ottawa Triathlon Club, Ottawa
- Ottawa-Carleton Association for Persons with Developmental Disabilities, Ottawa
- Otto's BMW, Ottawa
- Owl-Lite Rentals & Digital Imaging, Ottawa