Uspenski Cathedral (Finnish: Uspenskin katedraali, Swedish: Uspenskijkatedralen, Russian: Успенский собор, Uspenskij sobor) is an Eastern Orthodox cathedral in Helsinki, Finland, and main cathedral of the Orthodox Church of Finland, dedicated to the Dormition of the Theotokos (the Virgin Mary). Its name comes from the Old Church Slavonic word uspenie, which denotes the Dormition.

After Helsinki was made into the capital of Finland in 1812, Alexander I decreed in 1814 that 15 percent of the salt import tax were to be collected into a fund for two churches, one Lutheran and one Orthodox. Helsinki's Orthodox Church, considered to have formed in 1827 with the construction of the Holy Trinity Church, Helsinki, was in need of a larger church than before for a growing Orthodox parish. The construction of Uspenski Cathedral was largely funded by parishioners and private donors. The cathedral designed by the Russian architect Aleksey Gornostayev (1808–1862). The cathedral was built after his death in 1862–1868 and the work was led by architect Ivan Varnek. It was inaugurated on 25 October 1868. Used in construction of the cathedral, 700 000 bricks were brought over in barges from the Bomarsund Fortress that had been demolished in the Crimean War. The iconostasis is painted by Pavel S. Šiltsov. From the wish of Alexander II the church was dedicated to the Dormition of the Mother of God, uspenie.