CISS may refer to:
- CISS-FM, Canadian radio station
- Continuous Ink Supply System
- Center for Intelligence and Security Studies, a center at the University of Mississippi
- Concordia International School Shanghai,a coeducational day school Preschool to Grade 12 in Shanghai
- Computed Images System & Services division, a 1960s division of General Electric, now called "Genigraphics"
- Comité International des Sports des Sourds, "The International Committee of Sports for the Deaf"
- Canadian International School System