St Gregory's College is involved in representative sports as a Member of the Independent Sporting Association playing on Saturdays.
St Gregorys has two sports days every week. The College fields teams in Basketball, Cricket, Touch Football and Rugby Union in the Independent Schools Association (ISA) competition. The teams are made up of both boarders and day boys. Participation in the ISA Competition is in addition to competing in the weekly Metropolitan Catholic Schools (MCS) competition every Thursday.