Saint-Génis-des-Fontaines Abbey is a Benedictine abbey in Saint-Génis-des-Fontaines, Pyrénées-Orientales, France. It was dedicated to Saint Genesius and Saint Michael, to whom the surviving church is still dedicated.
The monastery is recorded for the first time in 819, in a document mentioning its abbot, Sentimir. Plundered and destroyed, it was rebuilt by order of King Lothair of France in 981.
Later it came under the protection of the Counts of Roussillon and later of the Kings of Aragon. The abbey church was enlarged and re-consecrated in 1153. In the 13th century it gained a marble cloister on the north-eastern side. Subsequently the abbey declined, and in 1507 was united with Montserrat Abbey.
During the French Revolution, the monks were expelled and the complex divided between several owners. The church was reopened to worship in 1846, as the village's parish church dedicated to Saint Michael. The cloister, which had been dismantled and sold, was bought back and re-installed in its original location in the 1980s.
The abbey church was most likely built at the same time as the original monastery, in the 8th century. Of the original church there remain some of the foundation structures, which show its plan to have included a main apse and two deep side apses, with a long transept.
The 1153 enlargement, with the addition of the vaulted ceiling over the transept and nave, led to the reconstruction of the walls in order to support the additional weight of the roof vaults. The ceilings of the apses were also modified and decorated with frescoes, of which only a few traces remain today. The church kept the Latin Cross plan typical of Romanesque architecture, with a nave, transept and three apses. In the 17th century the church was enriched with Baroque altars.