- Coastal Technologies Group, Inc.
- Cobalt Iron
- Cobol DataViewer
- Cobridge Communications
- Cobweb Solutions Limited
- CODA plc
- Codabar Barcode Font Package
- Code 11 Barcode Fonts
- Code 42 Software
- Code Rebel
- Code Sector
- codechain
- CodeFirst
- CodeFutures
- CodeGear
- Codejock Software
- CodeLynx
- Codemasters
- Codenomicon Ltd.
- Codenvy, Inc.
- Codeplay Software Ltd.
- CodeWarrior
- Codeworks, Inc.
- CoffeeCup HTML Editor
- CoffeeCup Software
- Cofio
- CoFluent Design
- Cogar Corporation
- Cogent Communications
- Cogent Data Solutions
- Cogistix LLC.
- Cogito Corporation
- Cognex Corporation
- Cognidox
- Cognis IT Advisors
- CogniTech
- Cogniview
- CogniVue Corporation
- Cognizant Technology Solutions
- Cognos
- Coherent Solutions
- Cohesion Corporation
- Coinbase, Inc.
- ColdLight
- Coleco
- Coleco Adam
- Coleco Alien Attack
- Coleco Electronic Quarterback
- Coleco Gemini
- Coleco Telstar
- Coleco Telstar Alpha
- Coleco Telstar Arcade
- Coleco Telstar Classic
- Coleco Telstar Colormatic
- Coleco Telstar Colortron
- Coleco Telstar Combat!
- Coleco Telstar Deluxe
- Coleco Telstar Galaxy
- Coleco Telstar Gemini
- Coleco Telstar Marksman
- Coleco Telstar Ranger
- Coleco Telstar Regent
- Coleco Telstar Sportsman
- ColecoVision
- Colin Tully
- Collabera Incentives
- CollabNet
- Collaborative Consulting
- Collaborative Drug Discovery
- Collaborative Fusion
- CollabraLink Technologies
- Collactive
- Collarity
- Collection of Rare Computers and Documents
- CollectiveView, Inc.
- collegefeed inc.
- CollegeMobile
- Collins Radio
- Colloquium (ISP)
- Colo5
- ColoCrossing
- Color 800/1000 Presses
- Color LaserJet
- Color LaserWriter 12/600 PS
- Color LaserWriter 12/660 PS
- Color StyleWriter 1500
- Color StyleWriter 2200
- Color StyleWriter 2400
- Color StyleWriter 2500
- Color StyleWriter 4100
- Color StyleWriter 4500
- Color StyleWriter 6500
- Color StyleWriter Pro
- Colorado Computer Museum
- Colorado Computer Support
- ColorGraphics Weather Systems
- ColorMonitor IIe/AppleColor Composite Monitor IIe
- ColorQube 8570
- ColorQube 8700