Xavier High School is an American independent university-preparatory high school for boys run by the USA East Province of the Society of Jesus, in the Chelsea neighborhood of the Manhattan borough of New York City, New York.

[6] A military-training unit began at the school in 1886 under the direction of the National Guard, and membership became mandatory in 1892.

[3] In 2008, Xavier High School announced that then President Daniel James Gatti would be retiring.

Upon ascending to the role, Raslowsky oversaw a development operation that leading to a significant physical expansion of the Xavier High School campus.

[11] Xavier, a Catholic High School Athletic Association (CHSAA) member, houses teams including baseball, basketball, bowling, cross-country, football, fencing, golf, hockey, indoor/outdoor track and field, rugby, soccer, lacrosse, swimming and diving, tennis, volleyball, and wrestling.

However, for many years, the teams were called the Cadets, a reflection of Xavier's military program, while a terrier was used as a mascot.

After a variety of replacements, including the 1980s Bruins, the nickname of the Knights was decided upon in the early 1990s and has been official since.

[13] Xavier has fielded one of the top rugby teams in the United States since the club's founding in 1976.

[17] Xavier High School's JV Soccer team won the CHSAA Intersectional Championship in 2008 and 2009.