AACS

AACS may refer to:


 * Advanced Access Content System, a standard for content distribution and digital rights management
 * AACS encryption key controversy
 * American Association of Christian Schools, an organization that unifies individual Christian schools and statewide Christian school associations
 * Annapolis Area Christian School, a Christian school in Maryland, United States
 * Attitude and Articulation Control Subsystems, used to orient space probes relative to a fixed point