Arsenoveszelyite, Cu2Zn(AsO4)(OH)3·2H2O, is a new supergene mineral from the Dongchuan copper ore field, Yunnan Province, China. It is the arsenic analogue of veszelyite and has been approved by the IMA CNMNC (IMA2021-076a). Arsenoveszelyite occurs as radiating aggregates or as individual lamellar crystals. Its colour ranges from cyan to emerald green, and it is closely associated with azurite and hemimorphite in the intensely weathered zones of the locality. Arsenoveszelyite has a Mohs hardness of 3–4 and a mean Vickers hardness of 265.0 kg/mm2. It shows good cleavage on {001} and {110}, is brittle with irregular fracture, and has a calculated density of 3.61 g/cm3. Optically, it is biaxial (+) with refractive indices nα = 1.655(10), nβ = 1.665(5), and nγ = 1.690(10); the optical orientation is defined as Y = b, and the measured 2V angle is 40°. The mineral is monoclinic, space group P21/c, with unit-cell parameters a = 7.5852(4), b = 10.3877(5), c = 9.8714(5) Å, β = 102.984(5)°, and V = 757.91(7) Å3. The crystal structure of arsenoveszelyite is characterized by the regular alternation of octahedral and tetrahedral sheets parallel to the (001) plane. The octahedral sheets comprise two distinct types of Cu-centred octahedra, while the tetrahedral sheets are formed by a combination of Zn- and As-centred tetrahedra. The empirical formula of arsenoveszelyite is (Cu1.69Zn0.30)Σ1.99Zn[(As0.81P0.20)Σ1.01O4](OH)3.03·2H2O. Arsenoveszelyite is the fourth new mineral identified in the Dongchuan copper ore field with arsenic as the dominant occupant of a crystallographic site, providing new insights into the mechanisms by which arsenic is immobilized in crystal structures during weathering in this area.