Crystals of Ba₃ZnSb₂O₉ have been grown by a high-temperature solid-state reaction and characterized by single-crystal X-ray diffraction. Ba₃ZnSb₂O₉ crystallizes in the hexagonal P6₃/mmc space group with a = 5.8663(4), c = 14.478(2) Å, V = 431.49(8) ų, Z = 2 and R (all data) = 0.0167. The structure of Ba₃ZnSb₂O₉ consists of pairs of face-sharing Sb₂O₉ bi-octahedra connected via corners with two single layers of mutually isolated ZnO₆ octahedra. Each Ba²⁺ ion is bonded to 12 oxygen atoms. The UV-vis absorption spectrum of the compound has been investigated. Additionally, the calculations of band structure and density of states have also been performed with density functional theory method. The obtained results tend to support the experimental data of the absorption spectrum.