Boloria eunomia, the bog fritillary or ocellate bog fritillary, is a butterfly of the Nymphalidae family.
The wings are orange brown with dark markings. The color of the hindwings are orangish brown with a tan postmedian band followed by a row of round silver spots. The length of the forewings is 20–24 mm. The butterfly may be threatened by bog hydrology. The butterfly flies close to the ground. They eat nectar from flowers including Labrador tea and goldenrod. The species flies from the end of May till the beginning of August.
Bog fritillary is found throughout the north-temperate region of the Northern Hemisphere including the Balkan Mountains of Bulgaria and one isolated population in Serbia. The species is commonly found in open acid bogs in areas that are moist. It can also be found in moist tudra and willow seeps.