The Sioni Cathedral of the Dormition is a Georgian Orthodox cathedral in Tbilisi, the capital of Georgia. Following a medieval Georgian tradition of naming churches after particular places in the Holy Land, the Sioni Cathedral bears the name of Mount Zion at Jerusalem. It is commonly known as the "Tbilisi Sioni" to distinguish it from several other churches across Georgia bearing the name Sioni.

Tbilisi, in some languages still known by its pre-1936 name Tiflis, is the capital and largest city of Georgia, lying on the banks of the Kura River with a population of around 1.2 million people. Tbilisi was founded in the fifth century AD by Vakhtang I of Iberia, and since then has served as the capital of various Georgian kingdoms and republics. Between 1801 and 1917, then part of the Russian Empire, Tiflis was the seat of the Caucasus Viceroyalty, governing both the northern and the southern parts of the Caucasus.