Royal Air Force Northolt or more simply RAF Northolt (IATA: NHT, ICAO: EGWU) is a Royal Air Force station in South Ruislip, 2 nautical miles (3.7 km; 2.3 mi) from Uxbridge in the London Borough of Hillingdon, western Greater London, England, approximately 6 mi (10 km) north of Heathrow Airport. As London VIP Airport, the station handles many private civil flights (private planes of up to 29 passengers) in addition to Air Force flights.

Northolt has one runway in operation, spanning 1,687 m × 46 m (5,535 ft × 151 ft), with a grooved asphalt surface. This airport is used for government and VIP transport to and from London.

Northolt predates the establishment of the Royal Air Force by almost three years, having opened in May 1915, making it the oldest RAF base. Originally established for the Royal Flying Corps, it has the longest history of continuous use of any RAF airfield. Before the outbreak of the Second World War, the station was the first to take delivery of the Hawker Hurricane. The station played a key role during the Battle of Britain, when fighters from several of its units, including No. 303 Polish Fighter Squadron, engaged enemy aircraft as part of the defence of London. It became the first base to have squadrons operating Supermarine Spitfire aircraft within German airspace.