Fairfax High School (FHS) is a public high school in the Eastern United States, located in Fairfax, Virginia, a suburb west of Washington, D.C. in Northern Virginia. The school is owned by the City of Fairfax, but is operated by Fairfax County Public Schools under a contractual agreement between it and Fairfax County.

The school building, which opened in 1973, is located on Blenheim Boulevard in eastern Fairfax. In 2007, FHS underwent a $54 million renovation designed by architectural firm BerryRio. Renovations began in October 2005 and added 86,500 sq ft (8,040 m²). of classroom space. Student numbers have increased at such a high rate that four trailers have been installed.

The previous school building and campus, which existed from 1935 to 1973, on Fairfax Boulevard was part of George Mason University for a time and then Paul VI Catholic High School from 1983 to 2020. It is now a retail space.