The Bachkovo Monastery of the Dormition of the Theotokos (Bulgarian: Бачковски манастир "Успение Богородично", Bachkovski manastir, Georgian: პეტრიწონის მონასტერი, romanized: p'et'rits'onis monast'eri), archaically the Petritsoni Monastery or Monastery of the Mother of God Petritzonitissa is a major Eastern Orthodox monastery in Southern Bulgaria. It is located on the right bank of the Chepelare River, 189 km from Sofia and 10 km south of Asenovgrad, and is directly subordinate to the Holy Synod of the Bulgarian Orthodox Church.

Founded as a Georgian Orthodox monastic center, Bachkovo is known and appreciated for the unique combination of Georgian, Byzantine, and Bulgarian culture, united by the common faith.

The monastery was founded in 1083 by Prince Gregory Pakourianos, a prominent Georgian statesman and military commander in the Byzantine service. Alongside the Iviron Monastery, Bachkovo was one of several Georgian monastic centers abroad, where Georgian monks produced original theological works, as well as translations of foreign religious texts, and sent them back to Georgia. Pakourianos required that his monks know the Georgian language. Among the monks on site was Ioane Petritsi, whose work would play a significant role in developing Georgian philosophy.

At the founding of Bachkovo, there was rivalry between the Byzantine Empire and the ascendant Kingdom of Georgia, with many Georgians suspecting that Greeks were trying to supplant them. According to Gregory Pakourianos's typikon for Bačkovo, which was written in 1083, "the Greeks are oppressors, covetous, scheming and unreliable. They used to take advantage of the Georgians' innocence and open-heartedness and strive to seize our monasteries." As a result of these tensions, Greeks were generally prohibited from being included in the monastery. Similar dynamics were present in other contemporary Georgian monasteries in the Balkans, such as the Monastery of Iviron in Greece, where the Greeks did eventually manage to take over.

At the monastery, Paskourianos also set up a seminary(school) for the youth. The curriculum included religion, as well as mathematics, history and music. In the 13th century, the Georgian monks of the Petritsioni (Bachkovo) Monastery lost their domination over the monastery, but their traditions were preserved until the beginning of 14th century.

During the time of the Second Bulgarian Empire, Bachkovo Monastery was patronized by Tsar Ivan Alexander, which is evidenced by an image of him on the arches of the ossuary's narthex. It is believed that the founder of Tarnovo Literary School and last patriarch of the mediaeval Bulgarian Orthodox Church, Patriarch Euthymius, was exiled by the Turks and worked in the school of the monastery in the early 15th century.

Although the monastery survived the first waves of Turkish invasion in Bulgarian lands, it was then looted and destroyed, but restored near the end of the 15th century. The refectory, whose mural paintings by an anonymous painter bear a significant artistic value, was reconstructed in 1601 and the Church of Mary, still preserved today, was finished in 1604.

Bachkovo Monastery is the final resting place of both Patriarch Euthymius (1330–1404) and Patriarch Cyril (1953–1971).