ICAO code may refer to:
ICAO airport code, a four-character alphanumeric code designating each airport ICAO airline designator, a three-letter code designating each airline ICAO aircraft type designator, a three- or four-character alphanumeric code designating every aircraft type (and some sub-types) that may appear in flight planning ICAO aircraft marshalling signals, visual signalling between ground personnel and pilots on an airport, aircraft carrier or helipad ICAO 24-bit address, allocation of 24 bit addresses to states to uniquely identify aircraft worldwide ICAO altitude code Gillham code, an encoding used in older aircraft to report altitudes