The Sremski Karlovci Orthodox Cathedral (Serbian: Саборна црква у Сремским Карловцима, romanized: Saborna crkva u Sremskim Karlovcima) is а Serbian Orthodox church in Sremski Karlovci, in Vojvodina, Serbia. The church is dedicated to Saint Nicholas.

The church is located next to the Patriarchate Court and it is the central church of the Eparchy of Srem. Historically it also served as a central church for the Metropolitanate and Patriarchate of Karlovci. The building was constructed in period between 1758 and 1762 during the term of Pavle Nenadović. Nenadović commissioned a project for the new representative baroque building during one of his multiple trips to Vienna. Zaharije Orfelin worked on the project in part related to baroque ornamentations of the two towers during his stay in the town in 1761–1762.

There was an older church dedicated to Saint Nicholas as well at the same location which was demolished prior to the beginning of the construction of the contemporary building. The new building was heavily damaged in blaze of 1799 with restauration lasting until 1805. The next general restauration took place in early XX century between 1909 and 1910.