Eusserthal Abbey (German: Kloster Eußerthal) was a Cistercian abbey in Eusserthal near Annweiler am Trifels in the Rhineland-Palatinate, Germany. All that now remains of it is the front portion of the abbey church, which is now used as a parish church.
The abbey was founded in 1148 by a knight, Stephan of Mörlheim, and settled by twelve Cistercian monks from Villers-Bettnach Abbey in Lorraine (of the filiation of Morimond). The monks' first task was the clearing of the river valley, to make it cultivable. In 1186 Emperor Frederick Barbarossa put the monastery under Imperial protection. It subsequently received rich gifts, including many vineyards in the south of the Palatinate. A village quickly grew up round the monastery.
The monks served at Trifels Castle as chaplains, and watched over the Imperial Regalia while they were kept in the castle during the 12th and 13th centuries. Eusserthal never founded any daughter houses, but it had a priory at Mörlheim.
After that the importance of the abbey declined. In the 15th century it was looted several times. In 1525, during the German Peasants' War, it was looted and set on fire; it was rebuilt in 1552 under Abbot Martin II. In 1561 Elector Frederick III dissolved the abbey in consequence of the Reformation.
In the 17th and 18th centuries several attempts were made to revive the monastery, but without success.