The Permanent Joint Headquarters (PJHQ) is the British tri-service headquarters from where all overseas military operations are planned and controlled. It is situated at Northwood Headquarters in Northwood, London. The Permanent Joint Headquarters is commanded by the Chief of Joint Operations (CJO), the position of which is currently held by Lieutenant General Charles Stickland.

Northwood is an area in the London Borough of Hillingdon, North West London, located 14.5 miles (23.3 km) north-west of Charing Cross. Northwood was part of the ancient parish of Ruislip, Middlesex. The area was situated on the historic Middlesex boundary with Hertfordshire, and since being incorporated into Greater London in 1965, has been on the Greater London boundary with that county.