- C5 stands for Channel 5 (United Kingdom)
- C5 stands for Class 5
- C5 stands for Fifth Generation Corvette (1997 – present; Chevrolet)
- C5 stands for Creating Connecting and Collaborating through Computing (conference)
- C5 stands for Comprehensive Combat and Complex Casualty Care
- C5 stands for Schedule V Controlled Substance (USA)
- C5 stands for Copenhagen Comprehensive Collection Classes for C#
C5