The acronym AOS may refer to the following:

• Acking, Olsson & Silow — the Swedish design company
• Acquisition of Signal the first instance of receiving a signal during an expected communications event.
• Adventures of Superman, a DC Comics ongoing comic book series
• Age of Sail — the pc game
• Agricultural Ontology Service - The Agricultural Ontology Service.
• Aria of Sorrow part of the Castlevania series
• Armed Offenders Squad — New Zealand police unit.
• Bluebottle OS — the computer operating system also known as AOS.
• IBM's Academic Operating System.
• The Aeon of Strife, an event in the StarCraft universe