氧化镧是镧（III）的氧化物，分子式为La₂O₃，室温下为白色粉末。氧化镧可溶于酸生成镧盐。

氧化镧通常利用草酸镧或者碳酸镧的热分解制备。

实验室可以用可溶性的镧盐和碱反应制备氢氧化镧，再使氢氧化镧受热分解得到氧化镧。

Lanthanum oxide is La₂O₃, an inorganic compound containing the rare earth element lanthanum and oxygen. It is used to develop ferroelectric materials, as a component of optical materials, and is a feedstock for certain catalysts.