Clarkson Secondary School is a high school in Clarkson community of Mississauga, Ontario, Canada; designated Ward 18 by the Peel District School Board. Clarkson is an average school in both population (11th, at 866 students) and age (13th, built in 1969) of the entire Peel range of 28 public secondary schools. It is also known as the "Peel Academy for International Students".

Clarkson was designed like many 1970s-era schools in Ontario as part of an experimental open concept design. On the ground floor, the cafeteria and auditorium are central to the design; a tech/drama wing, staff room, and gymnasiums are placed on the west side, while a classroom wing adorns the east side. These were open to the hallways, to other classrooms, separated only by pillars. Other schools using the same concepts include The Woodlands Secondary School, Bayridge Secondary School, and St. Thomas More Catholic School. During the late 1970s, the design was abandoned for a more traditional approach, as such designs proved deficient in the leakage of noise from other classes.

This article's list of alumni may not follow Wikipedia's verifiability policy. Please improve this article by removing names that do not have independent reliable sources showing they merit inclusion in this article AND are alumni, or by incorporating the relevant publications into the body of the article through appropriate citations. (January 2022)

• Don Biggs - Former professional ice hockey player
• Brad Boyes - NHL hockey player
• Francis D'Souza - CityTV Personality
• Sean Jones - R&B singer
• Don Kerr - Multi-instrumentalist and record producer
• Matt Kudu - CFL football player
• Nick Mardner – CFL football player
• Shaun Majumder - Comedian, writer, and actor
• M. H. Murray - Filmmaker
• John River - Rapper
• Camilla Scott - Actress and host of the television show The Camilla Scott Show
• Barbara Turnbull - Journalist and Activist for people with Disabilities
• Debbie Van Kiekebelt - Track & Field star and former Citytv personality
• Phil X - Session Guitarist
• Kiana Madeira - Actress

• Education in Ontario
• List of secondary schools in Ontario

• Clarkson Secondary School website