The Holy Trinity Cathedral, known in Finnish as Pyhän Kolminaisuuden katedraali, is an Orthodox church in the city of Oulu. It serves as the cathedral of the Oulu Metropolis, which is part of the Finnish Archdiocese of the Patriarchate of Constantinople.

The construction of the church was completed in the summer of 1957, designed by Finnish architect Mikko Huhhtala. The church was built for Russian refugees who suffered during the Finnish Winter War. The altar fresco was created by the famous Finnish icon painter of Japanese descent, Petros Sasaki.

Since the establishment of the Oulu Metropolis in 1980, the church has held the status of a cathedral. From 1998 to 2008, the church complex underwent a major renovation.

On January 11, 2015, the episcopal ordination of the fourth head of the metropolis, Ilia (Valgren), took place in the cathedral.