The Airport Security Unit is the airport police of the Hong Kong Police Force tasked with the security of the Hong Kong International Airport. The ASU was originally formed in 1977 as the Special Action Squad on standby for security at Kai Tak Airport and in 1978 following a review it was renamed as the Airport Security Unit and commenced patrolling the airport. In 1998, the ASU moved to the Chek Lap Kok Airport.

Airport police units are a security police agency assigned to perform law enforcement functions at airports. They provide a wide range of law enforcement duties and responsibilities including patrol, investigation, traffic flow management, and control and response to airport emergencies. Airport police provide enhanced safety to airport employees, and to passengers. Officers can be found at security gates, throughout the terminal area, and around the airport’s perimeter.