The interior of the church consists of three naves: the main nave for the clergy and nobility, and the side aisles for the people. The main chapel, made of Sevillian tiles in shades of blue, stands out. Also notable in the main nave is a large marble pulpit. The ceiling of this church collapsed in the Lisbon earthquake of 1755. A beautiful portal, framed by columns and typical Manueline motifs, such as the armillary spheres next to the Portuguese coat of arms, is also noteworthy.