Devotion yto the Blessed Virgin Mary was a very important aspect in his life, and he transmitted it to the Pious Schools. After he became a religious, he never signed his name as "Doctor Calasanz," but only as "Joseph of the Mother of God," and he gave to his order the title "Poor Clerics Regular of the Mother of God of the Pious Schools."

• He wrote and promoted the "The Crown Of The Twelve Stars," wherein he praises the Immaculate Conception and the The Assumption Of Mary, three centuries before they were declared dogmas.
• He prayed five psalms in honor of Mary every day. He recommended the daily recitation of the Holy Rosary, and he ordered his communities to celebrate with solemnity the seven feasts of Mary.
• He had a medal of Mary engraved which depicts her giving to a religious "the indissoluble bond of the vows."
• He also promoted for both students and adults different Marian Congregations.