Waterloo High School is a high school in Waterloo, Illinois, and is the only public high school in the Waterloo area.

In 2007, ground was broken on a new building. The school's cost is roughly $38 million. The school is built on 62 acres (250,000 m) of land and holds 1,400 students. The school has a total of 57 classrooms.

Waterloo High School has an auditorium that can hold 462 people. The school also has a fitness center and weight room used for PE students and athletes, four computer labs, a library, a cafeteria, band room, chorus room, and an engineering lab. The school has an interior courtyard area for agricultural classes.

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Waterloo High School has four Advanced Placement classes; AP Lang and Comp, AP Chem, AP Lit., and AP Calc. The school also offers 24 honors classes, three of which offer college credit. The school offers Running Start to sophomores who have a minimum GPA of 3.2 and are enrolled in Algebra II Honors which allows them to get a high school diploma and an associate's degree.

The school has a 20,040-square-foot (1,862 m) gym that holds a total of 2,000 people. The school has six tennis courts, one softball field, one baseball field, and a football/soccer field as well as the marching field and a track.

• Olga Hartman (1900–1974), zoologist specializing in polychaete worms
• David Meckler (born 1987), ice hockey player

• Waterloo High School website