- C4S stands for Carrera 4S (Porsche 911 model)
- C4S stands for Centre for Sustainability (Transport Research Laboratory; UK)
- C4S stands for Command, Control, Communications, and Computer Systems (US DoD)
- C4S stands for Chondroitin-4 Sulfate
- C4S stands for Computers 4 Seniors (Georgia)
- C4S stands for Camille Cascode Constant Current Source (current limit circuit)
- C4S stands for Clean for Stripper (band)
- C4S stands for Command, Control, Communications, Computers, and Surveillance
- C4S stands for Classified Computer Configuration Control System
- C4S stands for Craig 4 Spokane (Spokane, WA)
C4S