Ter Apel Monastery is a former monastery in the village of Ter Apel in the northeastern Dutch province of Groningen. It is the only monastery in the larger area of Friesland and Groningen that survived the Reformation in a decent condition, and the only remaining rural monastery from the Middle Ages in the Netherlands. The convent buildings house a museum for monastery and church history and for religious art, as well as two contemporary art galleries. The former lay church of the monastery still functions as a reformed church.

The Crosiers, formally known as the Canons Regular of the Order of the Holy Cross, abbreviated OSC, is a Catholic religious order of canons regular of Pontifical Right for men. It is one of the Church's oldest religious orders, and membership consists of priests and brothers who live together according to the Rule of St. Augustine.