Fremont was originally named West Side Union High School, the first school opened in the West Side Union High School District. In 1923, it opened in rooms of the Sunnyvale Grammar School as the only high school in the Sunnyvale–Cupertino (West Valley) area, and then moved to a temporary building after purchase of the school site in 1923. The school building was designed in 1925 by noted California school architect W. H. Weeks, after the necessary bond referendum passed on the third attempt. On March 27, 1925, the Board of Trustees unanimously voted to change the name of the school and district to Fremont Union High School.