CTC
- CBS Technology Center
- CTC (TV station)
- CTC Media
- CTT Correios de Portugal, S.A.
- Calcutta Tramways Company
- California Transportation Commission
- Cambridge Temperature Concepts
- Canadian Tire
- Canadian Tire Centre
- Canadian Tourism Commission
- Canadian Transit Company
- Canadian Transport Commission
- Canberra Theatre Centre
- Carbon tetrachloride
- Career and Technology Centre
- Central Texas College
- Central Texas Conference
- Central de Trabajadores de Cuba
- Centralized traffic control
- Ceylon Tobacco Company
- Chattahoochee Technical College
- Chiba Television Broadcasting Corporation
- Child tax credit
- Cincinnati Technical College
- Cinnamon Toast Crunch
- Circulating tumor cell
- City Technology College
- Clermont Transportation Connection
- Closed timelike curve
- Combat Team Conference
- Combating Terrorism Center
- Comcast Technology Center
- Common Toxicity Criteria
- Common Transit Convention
- Communities That Care
- Computer Terminal Corporation
- Confederación de Trabajadores de Colombia
- Connectionist temporal classification
- Continuous transaction control
- Cornell Theory Center
- Cost to company
- Counter Terrorism Command
- Counterterrorism Center
- Cracking the Cryptic
- Crimson Trace Corporation
- Crush, tear, curl
- Cryme Tyme Cenation
- Cyclists' Touring Club
- Institute of Security and Global Affairs
- Itochu Techno-Solutions
- Royal Calcutta Turf Club
- The Contemporary Theater Company
- United Nations Security Council Counter-Terrorism Committee
- Zilog Z80