Church of Saint Thaddaeus in Lučaj, Minor basilica in Luchay, Belarus.

The Church of Saint Thaddaeus in Lučaj is a three-nave cross-domed basilica with a two-tower narthex facade, built in 1766–1776. The main nave ends in a semicircular apse, and the three-tiered towers with corner pilasters and niches received cylindrical cupolas during a 19th-century rebuilding. Inside, the central nave has a cylindrical vault with lunettes, the walls are painted in grisaille imitating stucco, and a panel above the entrance shows two warriors with shields.

In 1731 the Main School of Vilnius set up a mission in Luchay, initially in wooden buildings. Construction of the brick church began in 1766 with donations from two Ogiński princes: Michał Kazimierz Ogiński on 24 May and Tadeusz Franciszek Ogiński on 17 July. It was consecrated on 4 September 1774 and finished in 1776; in 1779 the Jesuits were suppressed and the church's funds passed to the Commission of National Education.

The church's secondary dedication honours Saint Francis Xavier and Saint Hedwig of Silesia, added when the Vilnius chapter named it for the Apostle Thaddaeus on 4 September 1774. A large oval parish seal bore the Latin inscription 'ŁUCZAENSIS ✚ SANCTUS THADEUS PATRONUS ECLESIÆ'. The first recorded baptism, of Ignatius, son of Franciszek Lisicienok and Sophia of Karpavichy, took place in August 1774.

The church stands in Luchay, Vitebsk Region, and was returned to the parish on 16 May 1990. It is an active Catholic parish, so visits should be timed around services. The building suffered severe damage in World War II and later served as a warehouse, so some interior elements are restored rather than original.

The church's 1774 consecration gave it the double title of Saint Thaddaeus and Saints Francis Xavier and Hedwig. A large oval seal used in its registers read "ŁUCZAENSIS ✝ SANCTUS THADEUS PATRONUS ECLESIÆ", naming Thaddaeus as patron of the church.