Alexander Nevsky Cathedral, Petrozavodsk, Orthodox cathedral in Petrozavodsk, Russia.

Alexander Nevsky Cathedral is an Orthodox church building in Petrozavodsk made of brick with five distinctive domes. The structure displays neoclassical design features and stands prominently in the city's religious district.

Permission to build a factory church was granted on 25 April 1825, and the foundation stone was laid in July 1826. The church was funded by the state treasury and donations from workers of the Alexander Foundry. Architect Alexander Postnikov designed it, and engineer Pietro Carlo Maderni supervised construction until 1832. Bishop Ignaty consecrated the main altar on 27 January 1832.

The cathedral serves as a center for regular Orthodox worship and community gatherings in the city. People visit for services, especially during major religious holidays when celebrations draw many worshippers.

The cathedral stands on Zavodskaya Square, a short walk from Petrozavodsk's centre. Inside the fence is a memorial slab from the grave of the locally venerated blessed Faddey; memorial signs in the square honour Chernobyl liquidators and the city's 300th anniversary. A monument to Alexander Nevsky, consecrated by Patriarch Kirill on 3 June 2010, stands beside the cathedral.

The design competition was won by Alexander Postnikov of the Department of Mines and Saltworks; the Italian-born Pietro Carlo Maderni only supervised the construction from 1826 to 1832. The church was funded by the state treasury together with donations from the workers and servants of the Alexander foundry.