ACI

ACI may refer to:

• Accusative and infinitive aka Accusativus cum infinitivo, a construction in Latin grammar
• Access Control Item, used for Access Management. See also Access Control List.
• Aci Castello (Sicilian: Jaci Casteddu), a city and comune in the Province of Catania in Sicily, Italy
• Adjacent-channel interference, power from a signal in an adjacent channel
• Adriatic Croatia International Club, a chain of yachting marinas (referred to as ACI Marinas) operating in the Croatian part of the Adriatic sea
• Agencia Central de Intelligencia, Colombia's newly proposed national intelligent agency.
• Agincourt Collegiate Institute a secondary school located in Toronto, Canada
• Air Cargo Inc, an organization that provides information to the freight forwarding industry
• Air Crash Investigation, an alternate name for Mayday (TV series)
• Airports Council International, international trade group of the world's commercial aviation industry, based in Montreal, Canada
• Albertson College of Idaho, now known as the College of Idaho, a small liberal-arts college in Idaho
• Alderney Airport, from its IATA airport code
• American Collegiate Institute - Izmir Amerikan Lisesi, located at İzmir, Turkey
• American Competitiveness Initiative, a federal program intended to help America maintain competitiveness
• American Concrete Institute
• American Constitutional Initiative, a non-profit organization that promotes progressive change
• Arch Coal inc., A major U.S. coal mining company
• Aurora Cable Internet, a digital cable television, cable internet and VOIP provider in Aurora, Ontario
• Autologous chondrocyte implantation, a medical treatment for articular cargilage damage.
• Automatic Car Identification, a railroad barcode system that preceded Automatic Equipment Identification
• Automobile Club d'Italia, a member of the Fédération Internationale de l'Automobile
• ACI, the ICAO code for Aircalin
• ACI (Agence Congolaise d'Info) Congo news agency

Aci is also the shortened form of the local name of the Sicilian city Acireale