The church has stained glass on various windows and openings. The ones done by the stained glass maker Joan Vila-Grau since 1999 are outstanding; they are made of panes of different colours fixed with lead and concrete. In these pieces of stained glass, Vila-Grau symbolises specific themes through the masses of colour.
The first stained glass windows to be placed were in the transepts, and they express the symbology conceived by Gaudí.