Copper(II) selenite is an inorganic compound with the chemical formula CuSeO<sub>3</sub>. It forms orthorhombic crystals. A blue dihydrate exists.
Copper(II) selenite can be prepared from copper(II) acetate and selenous acid.
Copper(II) selenite can be used a catalyst for Kjeldahl digestion.
A copper selenite chloride with the formula Cu<sub>5</sub>(SeO<sub>3</sub>)<sub>4</sub>Cl<sub>2</sub> has been characterized by single-crystal X-ray diffraction.