Joint Base Langley–Eustis (IATA: LFI, ICAO: KLFI, FAA LID: LFI) is a United States military facility located adjacent to Hampton and Newport News, Virginia. The base is an amalgamation of the United States Air Force's Langley Air Force Base and the United States Army's Fort Eustis which were merged on 1 October 2010. The base was established in accordance with congressional legislation implementing the recommendations of the 2005 Base Realignment and Closure Commission. The legislation ordered the consolidation of the two facilities which were nearby, but separate military installations, into a single Joint Base, one of 12 formed in the United States as a result of the law.

Unlike other joint bases that share common perimeters, the two components are geographically separated by 17 miles. In January 2010, the Air Force reactivated the 633d Air Base Wing to assume host unit and installation support functions at each location. The installation assumed its full operational capability (FOC) in October 2010. The 633rd ABW commander is Col. John Allen, Jr., with Chief Master Sgt. Trae King as its command chief master sergeant. The 633rd ABW is responsible to Air Combat Command.