Church of St. Nicholas, Orthodox church in Pačetin, Croatia.

The Church of St. Nicholas is an Orthodox place of worship in Trpinja with a single nave extending from west to east and featuring Baroque architectural details. The building displays characteristic design elements from this style throughout its structure and exterior.

Construction of the church began in 1752 and was completed within three years; Bishop Sofronije Jovanović of Pakrac blessed it on 27 August 1755. A 1443 stone stećak inscribed in Cyrillic and Old Church Slavonic marks the site of a former monastery. The church was reconstructed in 1908, 1958 and 1986, and during the Croatian War of Independence in 1991 two shells damaged the altar area.

The iconostasis was erected in 1910, painted by Ivan Tišov and commissioned by the Government of the Kingdom of Croatia-Slavonia to raise the standard of church furnishings. Its framework is Byzantine Revival with classical elements, and the Virgin icon at the top shows Secession traits. The church's feast, the Transfer of the Relics of St. Nicholas, is celebrated on 22 May as the village's slava.

The church stands in Pačetin, a village within the Trpinja municipality of Vukovar-Srijem County, reachable by local road from the Vinkovci–Vukovar corridor. It is an active Serbian Orthodox parish church, so visits fit around services rather than fixed opening hours. A Cyrillic-inscribed stone stećak from 1443 stands on the site and is easy to miss.

A 1443 stone stećak inscribed in Cyrillic and Old Church Slavonic stands on the site, testifying that a monastery once occupied the ground before the church was built. The medieval tombstone is easy to miss beside the present building.