The interior distribution of the building is arranged around a longitudinal axis, in which two interior patios filter in the natural light. On the lower level, a wide central corridor, with large parabolic arches, facilitates the flow of students through the halls. On the first floor, the patios are surrounded by narrow hallways with tall, narrow, diaphragmed arches, as if it were an indoor cloister for the nuns.

The principal materials used are brick and stone, given that the project was carried out on such a limited budget. In spite of this, Gaudí introduced a few of ceramic decorative elements, which ended up causing a few arguments between he and Father Ossó. A story exists which says that in one of these arguments, Gaudí, fed up with Father Ossó always involving himself in Gaudí's work, yelled, "Worry about your own business! You lead mass, and I'll build houses!"

On the corners of the building and at the altitude of the third floor, Gaudí constructed brick, helicoidal pilars with the company coat of arms in ceramic. Above every corner appears the four-armed cross, which Gaudí was accustomed to including in his works.

The roof is flat, transitable, and ventilated, and out of it spurts a chimney much like the ones of Palau Güell.

Like so many other religious buildings, the College of the Teresians suffered attacks during the year 1936 (Spanish Civil War) and was invaded and sacked. The invaders burned the furniture, the blueprints with the original floorplans, and a some of the ornamental details that have still never been replaced.

Declared a Historical-Artistic Monument of National Interest in 1969, this work by Gaudí is a free interpretation of the Gothic style in that pointed arches have been replaced by parabolic arches.