Among the remaining buildings of the medieval mendicant orders, the Our Lady of Hungary Church is one of the largest. The buildings walls were made of crushed stone while for edges and some parts carved stone blocks were used. Standing on the main square of Keszthely, the Gothic building dedicated to Virgin Mary and the connecting monastery was commissioned to be built by István Laczkfy in 1386. An inscription on the triumphal arch states that Laczkfy built the church due to a pledge he made. He later bestowed to building complex to the Franciscan Order. Following the death of Louis the Great, Laczkfy turned againts Sigismund of Luxemburg for which the emperor commanded him to be beheaded. His body was laid to rest in the Franciscan church.

Due to the threat of the Ottoman Empire, under the guidance of an Italian engineer, Giulio Turco, the church and the monastery was turned into a stronghold around 1550. During the constant battles, the friars left the buildings. Though the Ottomans tried to conquer the stronghold many times, they never succeeded. The geography of Keszthely made is easier to protect the building, as in those times Keszthely was located on a peninsula. Surrounded by the water and swamps of Balaton, it was really difficult to approach. After the castle of Kanizsa was reconquered in 1690, the stronghold lost its strategical importance. The friars returned only 33 years later to the then ruined building and began renovating it immediately. The rebuilding was finished in 1730. Pál Festetics founded the gymnasium in Keszthely where the Franciscans were employed as teachers.

In 1878, the small wooden spire above the the facade of the church was removed by Tasziló Festetics and a new, 60 meter tall steeple was built based on the design by Mór Geisl. At that point, the rose window of the facade was taken out and built into the new tower. The previously covered Gothic windows were removed and new rose windows were put in their place by Miksa Róth. Also, the tombstone of the builder István Laczkfy was removed from the floor and built into the Southern wall of the chancel where is can be seen today.

In the spring of 1945, the retreating German troops set the Neo-Gothic steeple to fire. Its renovation was finished in 1948. During renovation in the 1970's, old frescoes were discovered under the plaster and their renovation was only finished in 1985. The series of frescoes covering the whole surface of the chancel is probably not the work of a single master but rather a whole workshop. The paintings were finished before the dedication of the church, sometime in the 1380's.