The Steven F. Udvar-Hazy Center, also called the Udvar-Hazy Center, is the Smithsonian National Air and Space Museum (NASM)'s annex at Washington Dulles International Airport in the Chantilly area of Fairfax County, Virginia. It holds numerous exhibits, including the Space Shuttle Discovery, the Enola Gay, and the Boeing 367-80, the main prototype for the popular Boeing 707 airliner.

The 760,000-square-foot (71,000 m²; 17-acre; 7.1 ha) facility was made possible by a $65 million donation in October 1999 to the Smithsonian Institution by Steven F. Udvar-Házy, an immigrant from Hungary and co-founder of the International Lease Finance Corporation, an aircraft leasing corporation. The main NASM building, located on the National Mall in Washington, D.C., had always contained more artifacts than could be displayed, and most of the collection had been stored, unavailable to visitors, at the Paul E. Garber Preservation, Restoration, and Storage Facility in Silver Hill, Maryland. A substantial addition to the center encompassing restoration, conservation and collection-storage facilities was completed in 2010. Restoration facilities and museum archives were moved from the museum's Garber facility to the new sections of the Udvar-Hazy Center.