| Abbreviation | Definition |
|---|---|
| ACS | Anglo Chinese School |
| ACS | Anglo-Chinese School |
| ACS | Avery Clooney School |
| ACSA | American Collegiate School of Architecture |
| ACSB | Anglo Chinese School Barker |
| ACSB | Association of Canadian Schools of Business |
| ACSC | Allen County Schools Cooperative |
| ACSD | Abbeville County School District |
| ACSD | Addison Central School District |
| ACSD | Albany County School District |
| ACSD | Albion Central School District |
| ACSD | Amherst Central School District |
| ACSD | Anaheim City School District |
| ACSD | Arlington Central School District |
| ACSEF | Alexander City Schools Education Foundation |
| ACSF | Asheville City Schools Foundation |
| ACSI | Anglo-Chinese School Independent |
| ACSIS | Athletic Conference of Singapore International Schools |
| ACSM | Associateship of the Camborne School of Mines |
| ACSOL | Association of Christian Schools of Liberia |