Trinity Grammar School is built on an Anglican foundation. The School is governed by a Council (appointed by ordinance of the Diocese of Sydney). The Archbishop of Sydney is President.

The School is one of the original members of the Combined
Associated Schools in New South Wales. The other members in the Association are Barker College, Cranbrook School, Knox Grammar School, St. Aloysius’ College and Waverley College. The Head
Master is a member of the Association of Heads of Independent
Schools of Australia, (A.H.I.S.A.) and of the Head Masters’
Conference (U.K.).

The Right Reverend G.A Chambers, O.B.E., D.D., subsequently Bishop of Central Tanganyika, founded the School in 1913 at Dulwich Hill, of which Parish - the Parish of Holy Trinity - he was then Rector.

The imposing property at Summer Hill, set in 8 hectares of land, was purchased in 1926, and the property at Strathfield shortly afterwards. The School consists of three separate but closely-linked establishments. A Senior and Middle School for Day and Boarding students located at the Summer Hill Campus, as well as a Junior School (Years 3 to 6); Preparatory and Pre-Kindergarten sections (Pre-School to Year 6) at the Strathfield Campus; and an Outdoor Education Centre at the Pine Bluff Campus.

The School has a complement of approximately 200 teachers and offers a wide and varied range of academic, vocational, sporting and co-curricular subjects and activities.

Our graduating HSC and IB students consistently perform well and the camaraderie and friendships that are built over the years of attendance at Trinity stay with the boys for their entire lives.

The Old Trinitarian Union is very active and the School keeps a database on Old Boys to inform them of important news, and invitations to reunions and events.