Mountbolus is blessed with windows of great beauty. Commissioned by Fr. O'Reilly from 1917 to 1921, the windows depict the fifteen Mysteries of the Rosary. In the Sanctuary area there are five very fine examples of Stained glass. All sixteen windows in the church are from the world famous Harry Clarke Studios in Dublin. The windows were restored and the church was stormglazed in 2000 at a cost of £36,000 (€45,710)