三氧化二锑（化学式：Sb₂O₃）是一种无机化合物。天然产物称锑华，俗称锑白。

三氧化二锑是白色立方晶系晶体，分子组成为Sb₄O₆，具有四面体构型，键长为（Sb-O）220pm±10pm。在570℃转变为正交晶系，为三角锥形无限链状结构，键长（Sb-O）200pm，键角（∠OSbO）81°、93°、99°。

Antimony(III) oxide is the inorganic compound with the formula Sb₂O₃. It is the most important commercial compound of antimony. It is found in nature as the minerals valentinite and senarmontite. Like most polymeric oxides, Sb₂O₃ dissolves in aqueous solutions with hydrolysis.