King Khalid International Airport is the largest airport in the world. Located at about 35 kilometers north of Riyadh, Saudi Arabia, this airport was designed by the architectural firm HOK, and Arabian Bechtel Company Limited. On behalf of Saudi Arabian government, Arabian Bechtel Company Limited served as the construction manager. There are three passenger terminals (out of five) in use. These five terminals have eight aero-bridges each. This airport also consists a mosque, car parking for 11,600 vehicles (both covered and uncovered), an additional Royal terminal which is exclusively for the use of kingdoms guest and Saudi Royal family, one of the world's tallest central control tower, and two 4,260 meters long parallel runways. The airport occupies an area of 375 Square kilometers which is second only to the King Fahd International Airport at Dammam. King Khalid International Airport (KKIA) replaced Riyadh Airport in late 1983. Riyadh airport is now a Royal Saudi Air Force airbase.

All, except terminal five, main passenger terminals in the KKIA were built in 1982 when the airport was opened for the first time. Terminal five was opened in 2016. All international flights, except Skyteam members (Saudia, Air France, Korean Air and Middle East Airlines are the Skyteam members) and Flynas uses Terminal one. Skyteam members use terminal two for their operations. Terminal three is currently closed for renovations but used to service until Terminal five was started. Terminal four is never been used. Terminal five is the newest terminal used by Saudia and Flynas for domestic flights. Terminal 1 to 4 is linked by the means of three 168 meters long linking buildings. Each terminal is triangular in shape. There is a modern VIPs terminal in the complex, also including restaurants, cafeterias, airlines offices, government departments, hotels and rent-a-car companies counters, banks, first aid clinics and commercial shops. Terminal five can serve 16 narrow-body or 8 wide-body aircraft. It is Saudi's first privately run airport terminal operated by Irish airport operator Dublin Airport Authority.

The Royal Pavilion, used by the heads of state and other VIP visitors, has open space, garden area, and fountains. Air bridges and escalators are there to enter the buildings from the parking area. Passengers at KKIA can utilize sidewalks for transportation. 1,196 meters of moving walkways are located in the three link buildings. There are additional 80 elevators and escalators for passenger conveniences.

The airport has trained firefighters with several modern firefighting vehicles in five separate fire houses. In front of the passenger terminals, one on either side of the mosque, two large three level garages have been constructed. They are connected with walkways. Escalators and elevators are available in these garages, as well as stairways between the different levels.