ACW

ACW may refer to:

Military

 * American Civil War
 * Air Control Wing, e.g.:
 * 116th Air Control Wing
 * 461st Air Control Wing
 * 552d Air Control Wing

Other

 * Acorn Cambridge Workstation, a microcomputer
 * Ancient Christian Writers, a book series
 * Anticlockwise
 * Arts Council of Wales
 * Ashfield–Colborne–Wawanosh, a municipality in Ontario, Canada
 * ISO 639-3 code for Hejazi Arabic, a language dialect