Alvastra Abbey, Medieval Cistercian monastery ruins in Västra Tollstad, Sweden.

Alvastra Abbey is a ruined Cistercian monastery at the foot of Omberg in Östergötland. Its church was consecrated in 1185; the surviving stone walls outline the church and convent buildings, while the graves of King Sverker I and other early Swedish royals lie within the ruins.

Alvastra Abbey was founded in 1143 by monks and lay brothers sent from Clairvaux, making it with Nydala the first Cistercian house in the Nordic countries. Queen Ulvhild, wife of Sverker I, invited the monks, and the land lay in Sverker's morning gift to her. The abbey church was consecrated in 1185; Sverker I, murdered near Alvastra in 1156, was probably buried in the unfinished church. The monastery founded Varnhem, Julita and Gudsberga and was dissolved around 1530 during the Reformation.

The abbey church served as a burial church for the Sverker dynasty in the early 13th century. King Sverker I, murdered near Alvastra in 1156, was probably buried in the unfinished church, and the graves of Kings Carl I, Sverker II and John I, as well as Queens Richeza the Elder, Benedicta and probably Ulvhild, are found in the ruins. Ulvhild Håkansdotter, wife of Sverker I, invited the monks according to Exordium magnum.

The ruins stand in the meadow at the foot of Omberg, in Västra Tollstad parish, and are reached on foot from the nearby car park. The site is open all year and has no entrance fee. The church walls and the ground plan of the convent buildings can be traced on the grass.

Ulf Gudmarsson, husband of Saint Bridget, retired to Alvastra near his estate Ulvåsa and died there in 1344; he was buried in his own chapel in the abbey. Bridget then moved into a house beside the monastery and stayed until she left for Rome in 1349.