Greek Catholic Co-cathedral of Saints Cyril and Methodius, Byzantine Revival co-cathedral in Gornji Grad, Croatia

The Greek Catholic Co-cathedral of Saints Cyril and Methodius is a single-nave church with a semicircular apse, designed by Hermann Bollé in the neo-Byzantine style of historicism. Its facade mosaics, ordered from Innsbruck, show Christ between Saints Peter and Paul at the top and Saints Cyril and Methodius in the middle. The 50-metre bell tower holds three bells, the largest weighing 782 kg.

A Greek Catholic church and seminary already stood on the Upper Town by 1681, serving believers from Žumberak, Uskoks and clerics; a 1766 fire destroyed the books that would date it precisely. In 1795 land was bought for 1,500 forints and a walled church of St. Basil the Great was built in 1799, holding an altar slab with relics of St. Honoratus and St. Fulgentius. Bishop Konstantin Stanić replaced it with a larger St. Basil in 1828; after the 1880 earthquake, Bishop Ilija Hranilović had today's church built in 1885–1886 by master Mihael Faleschini, funded with support from mayor Nikola Badovinac.

The parish serves Greek Catholics, largely from Žumberak, Uskoks and clerics living in Zagreb, and belongs to the Žumberak Vicariate of the Eparchy of Križevci. The iconostasis was first painted by Nikola Mašić, whose icons were rejected; the accepted ones are by Epaminondas Buczewski of Bukovina. Six portable icons for the tetrapod in the nave are by the sculptor Dekleva.

The church is located in the Gornji Grad neighborhood next to well-known landmarks and is easily reached on foot. Visitors should keep in mind that this is an active place of worship where visiting times should be respected.

The interior houses a rare collection of religious objects including a tetrapod cross and hand-crafted icon sets that are uncommon in most other churches. These items tell the story of Greek Catholic tradition and its forms of artistic expression.