Longmont High School is the city of Longmont, Colorado's original high school, opening its doors to students in 1901. The school is located in central Longmont and serves as the Honors/Advanced Placement Focus School for the St. Vrain Valley School District.

Athletics
The Longmont High School football team won the national championship in 1908. It went on to win its next Colorado state football championship in 1940, followed by back-to-back state titles in 1954 and 1955. However, the school is perhaps best known for its record streak, starting in 1988 and ending in 1992, in which the Trojans went 45-0, winning three consecutive championship crowns. It remains the longest winning streak in Colorado football history.

Music
The Longmont High School Band in commissioned Joy Revisited by Frank Ticheli in 2005. The Longmont High School Band later commissioned "Ostinato" by Richard Saucedo in 2010
The Longmont High School Drumline has competed in Percussion Scholastic World (PSW) in 2001 Percussion Scholastic Open(PSO) winning two state championships from 2002–2006, Percussion Scholastic National A PSNA (in RMPA competition 2009)from 2007-2009 winning state in 2009, and in Percussion Scholastic A (PSA) from 2010 to present. The Longmont High School Drumline also travels almost every year to the WGI competitions. The Longmont Drumline has been a 6 time WGI World Championship finalist


Notable alumni
Vance D. Brand – Former NASA astronaut, test pilot, mission commander and engineer.
Greg Biekert – Former Linebacker for the Oakland Raiders and Minnesota Vikings.
David Pauley – Pitcher for the Detroit Tigers.
Eric Coyle – Former Center for the Washington Redskins.
Vince Rafferty – Former Center and Guard for the Green Bay Packers.
Kimiko Hirai-Soldati – Former U.S. Olympian, springboard and platform diving.
Rick Reilly - Writer for ESPN the Magazine and ESPN.com.