Saint Nikolai Cathedral (Russian: Николаевский собор, Armenian: Սուրբ Նիկոլայ Մայր եկեղեցի (Surb Nikolay Mayr yekeghets'i)) was a Russian Orthodox cathedral in Yerevan, Armenia.

It was located at the site of what is now Shahumyan Square in Yerevan's Kentron District.

According to O. Khalpahkhyan, this Russian military cathedral at the central square of Yerevan, was built in the second half of the 19th century.

The cathedral was built by local red and black tufa in the architectural forms that prevailed at that time in Russia.

This article about a church building or other Christian place of worship in Armenia is a stub.