Sydney Boys High encourages participation in team sports for educational reasons. Team sports build a sense of belonging in boys, a connectedness with the school; teamwork skills are developed; individual self-confidence and self-esteem are enhanced through group endeavour; and socialisation at school is fostered through ready topics of conversation among team members. Teams help and protect their members.

Sydney Boys High is unique among NSW state secondary schools due to its membership since 1906 of the Athletic Association of Great Public Schools, formed in 1892 to order and regulate sporting fixtures for schools with senior students. The other eight members of this Association (commonly called the 'GPS') are private schools.

The school expects students to engage in at least one GPS sport per year. This commitment includes Saturday competition. We encourage boys to get involved in aerobic fitness activities (the athletics and cross country programs) to help them in their chosen sports. To help their strength in anaerobic activities we offer supervised weights training.

The policy of the school is that sport is compulsory all year for students in Year 7, Year 8, Year 9, Year 10 and Year 11 and for two terms in Year 12. Those students who are unable to participate in Saturday sport are to address this in writing with complete details to the Head Teacher-Sport at the beginning of the year.

It is the policy of the school to support GPS sports in the season that they are contested by the members of the Athletic Association of the Great Public Schools.

This means that equipment costs, venue hire, travel to certain venues, particular coaching fees, competition entry fees, charges for referees or umpires, capitation fees and entry fees for knockout competitions, are paid for from school funds. Competition entry fees for representative teams for all sports are paid for from school funds. The school charges parents a global fee and in addition, a sports levy, to cover these costs.