St Paul's has many breathtaking stained glass windows. The most significant, however, is the The Great War Memorial Window (above the main entrance porch and vestibule). 'This window is dedicated to the glory of God, and in loving and thankful memory of those of Otago and Southland who gave their lives in the Great War, 1914 – 1918.. The theme of this elaborate work is "Through sacrifice and death — to victory and peace." The window was made by James Powell and Son, Whitefriars, London, the money gathered by subscriptions canvassed throughout Otago and Southland.
It includes eight significant panels, each with an image of an angel. The angel of death bears a scythe and the angel of peace bears leaves of peace.
The window represents Victory (right-hand half) through Sacrifice (left-hand half) symbolised by the Golden Crown and the Crown of Thorns respectively in the upper tracery. Within the tracery sections are the Coats of Arms of the Otago and Southland Regiments, and the Arms of New Zealand and the United Kingdom.
The top line of figures consists of (1) St. Michael the Warrior Angel; (2) the Angel of Suffering; (3) Sacrifice; (4) Death; (5) Gabriel the Archangel of Peace; (6) Angel with Chalice of Remembrance; (7) of the Resurrection; and (8) Victory with the Crown of Glory.
The central line symbolises Fortitude, Patience, Truth, Obedience, Love, Faith, Hope, and Peace.
The bottom line uses new symbols for the top themes: War in Heaven, the Paschal Lamb, Moses lifting up the serpent in the wilderness, the Entombment, the Nativity, Christ reigning from the Cross, and the Resurrection and Ascension.