- CACTUS stands for Capital Area / Central Texas Unix Society
- CACTUS stands for Converted Atmospheric Cherenkov Telescope Using Solar-2 (observatory; Daggett, CA)
- CACTUS stands for Computer Aided Credentials of Teachers in Utah Schools (database; Utah State Office of Education)
- CACTUS stands for Calculator and Computer Technology User Service (website; teacher services)
- CACTUS stands for Cohousing Association of Central Texas Umbrella Services (Austin, TX)
CACTUS