IACS may refer to:
- Indian Association for the Cultivation of Science
- Industrial Automation and Control Systems
- Innovation Academy Charter School
- Integrated Administration and Control System
- Integrated Adults Careers Service
- International Annealed Copper Standard, a unit of electrical conductivity for metals and alloys relative to a standard annealed copper conductor; an IACS value of 100% refers to a conductivity of 5.80 × 10 siemens per meter (58.0 MS/m) at 20 °C.
- International Association for Communication and Sport
- International Association of Classification Societies
- International Association of Cryospheric Sciences
- Individuals Authorized to Access to CMS computer Services
- Internet Access Control. A hosted and remote administered security solution by Bric Security LLC.