Saint Basil Cathedral, Eastern Orthodox cathedral in central Tripoli, Greece

Saint Basil Cathedral is an Eastern Orthodox church in central Tripoli featuring a symmetrical facade with ornamental details typical of Orthodox religious architecture. The entire exterior is covered in marble from Doliana, giving the building a bright and formal appearance throughout.

A fire destroyed Tripoli's centre on 7 July 1855, clearing the ground for the new cathedral, founded that year by an unknown architect. Work paused in 1862–1863, resumed in 1864–1868 under the engineer Athanasios Politopoulos, and N. Pantzeiris designed the pediments and dome in 1878. The church opened in August 1882, was inaugurated on 3 June 1884, and gained its two bell towers in 1903 and 1905.

The cathedral is the seat of the Metropolis of Mantineia and Kynouria. Its marble iconostasis was designed by Ernst Ziller, the wall paintings were made by Konstantinos Lokis and finished in 1927 or 1928, and the icons flanking the sanctuary entrance were painted by Konstantinos Artemis in 1918. A fire in October 1995 damaged the narthex and destroyed parts of the vaulted ceiling decoration.

The cathedral faces Plateia Agiou Vasileiou, the square laid out around it before the rest of Tripoli's street plan was drawn. The west door, flanked by the two bell towers, is the main entrance. It is an active metropolitan church, so visits fit around services; the narthex ceiling lost part of its decoration to a fire in October 1995.

The church's orientation and size were fixed by the Bekir Pasha mosque that stood here before the Greek War of Independence; tradition holds the building was begun as a mosque. The square around it was laid out first, and the street plan of Tripoli was then drawn from the church as the reference point.