Fontainejean Abbey, otherwise Fontaine-Jean Abbey (French: Abbaye de Fontainejean or Fontaine-Jean), was a Cistercian monastery in the commune of Saint-Maurice-sur-Aveyron in the Gâtinais in the département of Loiret, France.
It was founded in 1124 as a daughter house of Pontigny Abbey by Miles de Courtenay, who had previously also founded Les Écharlis Abbey. Fontainejean became the burial place of the Courtenay family. It was occupied by Protestant troops in 1562, when the church was ruined. The abbey was suppressed during 1791 in the French Revolution.
Little remains of the structures except for the north arm of the transept of the church with chapels and part of the wall of the choir, and also part of the 13th-century grange.