Webster Groves High School began as a general course offered to ninth graders in 1889.
At the turn of the century, the high school occupied the first floor of the original Bristol School building; the elementary school occupied the second floor. Sarah Milligan was the first high school teacher. George L. Hawkins was the first high school principal in 1905. As enrollment increased, the high school used hallways and store rooms as supplementary classrooms.
In 1906 the high school was built on Selma Avenue, a two-story brick building with three classrooms and an auditorium. Six teachers, including the principal, made up the faculty. The principal taught six classes daily and supervised a study hall in the auditorium.
The front wings were added to the building in 1913; the left wing, a gymnasium; the right wing, an auditorium. In 1917 the Webster Groves Armory was erected, and after World War I was turned over to the high school as the senior gymnasium and lunchroom. The building was replaced in 1946 by Roberts Gym, named after Charles A. Roberts, who taught and coached at WGHS for 39 years. Webster Groves High School was originally named Hamsher High School after Frank Hamsher, school superintendent from 1917 to 1924.
In 1966 the three-story wing was added to the rear of the building. In the same year, the Herbert Schooling Library was dedicated. Many of the features have been preserved, including the original fireplace, resulting in a blend of old and new.
Memorial Field was built in the 1940s and dedicated as Moss Field in 1974, in honor of Ray Moss, head football coach for 25 years, until the Turkey Day game of 1964. Bleachers were added to the stadium in 1978, lights in 1979, and a new all-weather track in 1984. A locker room was added in 1990.
The high school has received a Silver Award for its use of Positive Behavioral Interventions and Support.
In 2012, a 106,350-square-foot addition at the north end of the high school, made possible by a $36 million zero-tax-increase bond issue opened. The new wing includes space for industrial technology, visual art, music, social studies, and science.