SEAC
- SEAC (computer)
- SESAR European Airports Consortium
- Senior Enlisted Advisor to the Chairman
- Senior Enlisted Advisor to the Chiefs of Staff Committee
- Society for Ethics Across the Curriculum
- South East Asia Command
- South East Atlantic Conference
- Southeastern Athletic Conference
- Sri Lanka Broadcasting Corporation
- Student Environmental Action Coalition
- The Society for Electroanalytical Chemistry
- Wye College