Sandwich Secondary School is a school in LaSalle, Ontario. It has about 1,050 students, and teaches about half of the students in LaSalle, along with St. Thomas of Villanova Catholic Secondary School. Sandwich Secondary School is part of the Greater Essex County District School Board, or GECDSB. It was named after the former town of Sandwich, which used to encompass the western shores of Windsor, as well as LaSalle.

Prior to the opening of the school building in 1975, high school students in LaSalle were bused to General Amherst High School.

Sandwich Secondary's track-and-field complex, named the Robert C. Carrick Memorial Track, opened in 1993 at a cost of $1.70 million and includes an 8-lane rubberized all weather track, field house, grandstand, football and soccer field, baseball diamond, track and field event area (shot-put, a discus circle, all weather javelin approach, all weather runways for long jump, triple jump, pole vault), and a concession stand. The complex was named after a police officer who was killed in the line of duty in 1968 and is home to the Sandwich Sabres Men's Football team. Many nearby schools utilize the complex for their own track-and-field events. Sandwich Secondary also has a French immersion program for those coming from French immersion grade schools along with an English public schooling.

Its feeder schools, or family of elementary schools, are Sandwich West Public School, LaSalle Public School, Sacred Heart Roman Catholic School, Legacy Oak Trail Public School, James L. Dunn Public School, and École Bellewood Public School.

Sandwich Secondary School has many sports teams including basketball, volleyball, soccer, baseball, wrestling, ultimate Frisbee, squash, track and field, tennis, cross country running, football, curling, hockey, swimming, badminton, and softball.

Sandwich has won many recent titles in many different sports. The Sabres won the 2022 OFSAA Track and Field Championships.

Their Ultimate Frisbee Team were the 2022 SWOSSAA Champions and Competed at the OFSAA Championships in Toronto.

Sandwich's open doubles Tennis team of Carter Furmanek and Vishaal Metha, also won the SWOSSA Championships in 2022.

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• Jeff Martin — vocals, guitar, The Tea Party
• Kylie Masse — Olympic swimmer
• Kamau Peterson – former CFL player
• Amanda Reason — Olympic swimmer and former women's 50-metre breaststroke world record-holder (long course)
• Sofia Shinas — actress
• Christian Vincent — professional dancer, choreographer, actor and model

• Education in Ontario
• List of secondary schools in Ontario

• Sandwich Secondary School