The term SEAC can stand for:
- Senior Enlisted Advisor to the Chairman of the United States Joint Chiefs of Staff, the senior non-commissioned member of the United States armed forces
- SESAR European Airports Consortium, the operators of six major European airports joined forces for participation in SESAR
- South East Asia Command, a World War II Allied military command
- Standards Electronic/Eastern Automatic Computer, a first-generation electronic computer built in 1950
- Student Environmental Action Coalition, a coalition of environmental groups in the United States and Canada