The College crest was designed by parent and architect, Iris Rossen, in October 1976. She had in mind four factors: impact, meaning, artistry and practicability. The College Crest reflects the way that, historically, the image of justice and right harmony was developed in the three-dimensional Byzantine tower architecture. This superimposed the dome, representing the circle of eternity, on the base of the solid, earth-bound square. The whole is surmounted by the Cross in which the harmony is centred and from which justice flows.

All this is represented in the John XXIII College crest in the single dimension by the simple traditional symbols of the square, the circle and the Cross. The linear version, complete within itself, has, also, the openness and freedom of spirit which is envisaged for the College. The College colours, deep royal blue, gold and white are based on the school colours of Loreto and St Louis.