Dreifaltigkeitskloster, Religious historic site and hospital in Lutsk Raion, Ukraine.

The Trinitarian Monastery in Lutsk survives only as its 1729 monastic cells at 4 Senatorky Levchanivskoi Street, a national architectural monument. The former Baroque church of Archangel Michael and Apostle Paul, consecrated in 1729, was rebuilt in the Classical style before the mid-19th century and later abolished; the P-shaped monastery once enclosed an inner courtyard.

The Trinitarian Order was established in Lutsk in September 1717 and received the old Orthodox Church of St. Michael in 1718 on condition that it be repaired and keep its dedication. The order's superior, Piotr Lubieniecki, obtained a fund of 60,000 zlotys from Paweł Majkowski, treasurer of Bracław, and the monks built a Baroque church, consecrated on 11 November 1729 to Archangel Michael and the Apostle Paul. The old church was demolished. In 1849 the church was suppressed, and in 1863 it became a prison for political detainees, including participants in the Polish uprising.

The monastery's interior frescoes were painted by the Trinitarian artist Josef Prechtl and showed the order's work across the Polish-Lithuanian Commonwealth; a cycle of 30 scenes in the monastery told the lives of the order's founders, Saint Felix de Valois and John of Matha. The house also held the Bibliotheca collegii Luceoriensis ordinis Trinitatis, a library keeping historical documents on political events and other Catholic orders.

Only the 1729 cell building survives, at 4 Senatorky Levchanivskoi Street in the Pomostychi district north of the old town. The former church and its monastery courtyard are gone, so there is no religious or medical facility to visit; the structure is a national architectural monument seen from the street. Look for the surviving monastic cells rather than a church.

The icon of Saint Ignatius, painted in the mid-18th century, shows the Trinitarian church beside a fragment of Lutsk's castle buildings; it may have been made for this monastery. The church's interior frescoes were painted by the Trinitarian artist Jozef Prechtl, including a cycle of 30 scenes on the lives of Saint Felix de Valois and John of Matha.