Manglisi Cathedral or Manglisi Sioni Cathedral (Georgian: მანგლისის სიონი) is a 6th-7th-century Georgian Orthodox cathedral near the town of Manglisi, Tetritsqaro Municipality, Georgia.
The first church was built in 4th century. The current cathedral was constructed from the 6th to 7th centuries. The cathedral went through a huge restoration in 1002.
The temple has rather unique design. It is a tetraconch, rather common for the churches of the 6th-7th centuries, but unusually inserted into an octagon. Later alterations partly mask the original plan.