Acey Abbey (French: Abbaye d'Acey; Latin: Aceyum) is a Cistercian abbey founded in 1136, and occupied since 1873 by Trappist monks. It is located in Vitreux in the department of Jura, France, on the River Ognon, about 26 kilometres north-north-east of Dole and about 7 kilometres north of Gendrey.
The abbey was built in 1136 at the instigation of the Archbishop of Besançon, Anseric de Montréal, and of Renaud III, Count of Burgundy, about 5 kilometres distant from an existing settlement of hermits. The initial community of monks were from Cherlieu Abbey, and Acey was therefore of the filiation of Clairvaux. The new foundation grew rapidly and had soon built six granges. In 1184 it was able to found a daughter house, Pilis Abbey in Hungary (dissolved in 1526). At the end of the Middle Ages it fell into the hands of commendatory abbots.
Its location on the boundary of the Free County of Burgundy and the Duchy of Burgundy caused it to be involved in warfare in 1435 and 1477, in 1569 during hostilities with Protestants and in 1595 under King Henry IV of France.