Boloria oscarus is a small butterfly found in the East Palearctic that belongs to the browns family.

This rather large species differs above but little from its nearest allies, but is distinguished beneath by the median band being very regular and the silvery gloss entirely absent.

The median band is wax-yellow throughout, and the marginal spots, which also are silvery in allied species, are white with a feeble silky gloss.

(67h) is the large southern form from the Ussuri and Corea; the upperside is of a pure and brighter colour, the black markings being more prominent.

— The species flies in swampy meadows and in places with brooks, being plentiful in some localities, in May and June.