- ACIU stands for Arbejdsmarkedets Center for Internationale Uddannelsesaktiviteter (Danish: Social Center for International Training; Denmark)
- ACIU stands for Advanced Central Interface Unit
- ACIU stands for AUTODIN Conferencing Interface Unit
- ACIU stands for Abiriba Communal Improvement Union (Nigeria)
- ACIU stands for Allied Counterintelligence Unit
ACIU