The Trinity Church, known in Estonian as Mustvee Halastuse ja Püha-Kolmainsuse Ühisusu kirik, is an Orthodox church in Mustvee, Estonia, and is under the jurisdiction of the Estonian Apostolic Orthodox Church of the Ecumenical Patriarchate.

Built in 1877 as a Old Believer church, it functioned until 1957 when its icons and church items were transferred to the new rite Nicholas Church. In 2000, it was registered as "Holy Trinity Old Believer Parish of Mercy" within the Estonian Orthodox Church of the Moscow Patriarchate. However, the church building was returned by the Estonian government to the Estonian Apostolic Orthodox Church of the Ecumenical Patriarchate.

On May 1, 2003, the Estonian Apostolic Orthodox Church transferred the church building to the Old Believer community for free use, and on May 31, 2004, the church was reopened. Subsequently, it became a new rite church and came under the jurisdiction of Constantinople.