Westmalle Abbey, otherwise the Trappist Abbey of Westmalle, is a monastery of the Cistercians of Strict Observance in Westmalle in the Belgian province of Antwerp.

The Trappists, officially known as the Order of Cistercians of the Strict Observance and originally named the Order of Reformed Cistercians of Our Lady of La Trappe, are a Catholic religious order of cloistered monastics that branched off from the Cistercians. They follow the Rule of Saint Benedict and have communities of both monks and nuns that are known as Trappists and Trappistines, respectively. They are named after La Trappe Abbey, the monastery from which the movement and religious order originated. The movement first began with the reforms that Abbot Armand Jean le Bouthillier de Rancé introduced in 1664, later leading to the creation of Trappist congregations, and eventually the formal constitution as a separate religious order in 1892.