The buff ermine (Spilarctia luteum) is a moth of the family Erebidae.

It is found throughout the temperate belt of the Palearctic region south to northern Turkey, Georgia, Kazakhstan, southern Siberia (excluding Buryatia), eastern Mongolia, Amur Region, China, Korea and Japan.

The wings of this species are buffish yellow (the males tend to be more yellow than the females) and are typically marked with a diagonal row of dark spots on the forewing and a few other scattered spots on both forewings and hindwings.

The species flies from May to July in the British Isles.

It is polyphagous, feeding on a wide variety of trees, shrubs and herbaceous plants (see list).