The school was built in 1971 and is situated on 14.64 acres. The Diefenbaker building is unconventional in its design and includes individual classrooms, large open areas, small conference rooms, and a variety of specialized program offerings to take full advantage of the unique spaces available. In 1990, an addition was made on the southeast corner to add a second gymnasium, science and math classrooms, and the Mall area. A space enclosed under the gymnasium in 1990 allowed for the relocation of the communications technology room. The school has 43 classrooms, 2 gymnasiums, 3 computer labs, and many independent computer workstations for student use, all of which are networked through the central hub. John G. Diefenbaker also has a music room, a newly developed drama facility, home economics, industrial arts labs, and a library. It is a culturally diverse school with 40 different languages being spoken in student's homes. As a learning community, it promotes excellence, provides opportunity, and values diversity. Diefenbaker believes students have the right to access meaningful education that will provide them with opportunities to become productive citizens and pursue desired futures.

Why John G. Diefenbaker High School

• Course variety: Diefenbaker is proud to offer the International Baccalaureate (IB) diploma program. It has unique programming for English Language Learners (ELL) and International Students. Diefenbaker has extensive Fine Arts, Career and Technology Studies, and Digital Media Arts programs including Dance, Graphic Design, and Yoga.
• Extracurricular activities: Clubs and activities at Diefenbaker include STUCO (Student Council and Leadership), Humanitarian and Global Initiatives (Make a Change Africa, Amnesty International, Youth Volunteer Corps), Green Chiefs Environmental Club, Model Parliament, Speech and Debate, Gay-Straight Alliance, Math Contests and Skills Competitions, Culture Club and Youth Cultural Ambassador Training Program (CCIS), Yearbook, and Student Voice Newspaper, to name just a few. Sports teams include Badminton, Basketball, Cross Country, Field  Hockey, Football, Rugby, Soccer, Swim Team, Track and Field, Volleyball, and Wrestling.