氧化铒，化学式Er₂O₃。

粉红色粉末，不溶于水，可溶于酸：

Er₂O₃ + 6 H → 2 Er + 3 H₂O

Erbium(III) oxide, is synthesized from the lanthanide metal erbium. It was partially isolated by Carl Gustaf Mosander in 1843, and first obtained in pure form in 1905 by Georges Urbain and Charles James. It has a pink color with a cubic crystal structure. Under certain conditions erbium oxide can also have a hexagonal form. Erbium oxide is toxic when inhaled, taken orally, or injected into the blood stream in massive amounts. The effect of erbium oxides in low concentrations on humans over long periods of time has not been determined.