The International Civil Aviation Organization (ICAO), pronounced , (in French: Organisation de l'aviation civile internationale, OACI ), is a specialized agency of the United Nations. It codifies the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. Its headquarters are located in the Quartier International of Montreal, Quebec, Canada.
The ICAO Council adopts standards and recommended practices concerning air navigation, its infrastructure, Flight inspection, prevention of unlawful interference, and facilitation of border-crossing procedures for international civil aviation. In addition, the ICAO defines the protocols for air accident investigation followed by transport safety authorities in countries signatory to the Convention on International Civil Aviation, commonly known as the Chicago Convention.
The ICAO should not be confused with the International Air Transport Association (IATA), a trade organization for airlines also headquartered in Montreal, or with the Civil Air Navigation Services Organisation (CANSO), an organization for Air Navigation Service Providers (ANSP's) with its headquarters at Amsterdam Airport Schiphol in the Netherlands.