This is an alphabetical list of companies that have at one-point or another been based in Ottawa:

• Abacus Data
• Alterna Savings
• Atkinson Film-Arts
• Bank of Ottawa
• Bell-Northern Research
• BreconRidge
• Bridgewater Systems
• Brookstreet Pictures
• Bruised Tongue
• Campeau Corporation
• Canada Deposit Insurance Corporation
• Canada Mortgage and Housing Corporation
• Canada Post
• Canadian Bank Note Company
• Canadian Broadcasting Corporation
• Canadian Commercial Corporation
• Ciel Satellite Group
• Cognos
• Corel
• CPAC (TV channel)
• CPCS Transcom Limited
• Defence Construction Canada
• Doyle Salewski Inc
• DragonWave
• Ekos Research Associates
• ENCON Group Inc.
• Epiphan Systems
• Eurocom Corporation
• Export Development Canada
• Farm Boy
• First Air
• Freimans
• Fuel Industries
• Funbag Animation Studios
• Gabriel Pizza
• Gandalf Technologies
• Giant Tiger
• Halogen Software
• Hydro Ottawa
• Ingenia Communications Corporation
• International Development Research Centre
• Iogen Corporation
• Kelp Records
• Klipfolio
• Knight Enterprises
• Kongsberg Gallium Ltd.
• KRP Properties
• Lacewood Productions
• Lee Valley Tools
• Level Platforms
• Loeb (supermarket)
• Lumenera
• Magma Communications
• Market Fresh
• Marshes Golf Club
• MediaMiser
• Mercury Filmworks
• MicroSystems International
• Minto Group
• Mitel
• MKC Networks
• NABU Network
• Neptec Design Group
• Newbridge Networks
• Nordion
• Le Nordir
• Ogilvy's
• Ottawa Car Company
• Ottawa Central Railway
• PlaSmart
• Pleora
• Pronexus
• ProntoForms
• Protecode
• Protus
• Public Sector Pension Investment Board
• Pure Spring Company
• QNX Software Systems
• Quickie Convenience Stores
• Red Quill Books
• SAW Video Mediatheque
• Shopify
• Siemens Healthineers
• Signority
• Skycron
• Solace
• Solidum Systems
• Spiderwort
• Tablo (DVR)
• Telesat
• Ten Broadcasting
• Tundra Semiconductor
• Versaterm
• West Wholesale
• Wilderness Tours
• Zarlink