The Northwestern fritillary (Speyeria hesperis) is a butterfly of the Nymphalidae family. It is found in the Northwestern United States and Western Canada, as far east as Manitoba and the Dakotas. With a wingspan of between 45–58 millimetres (1.8–2.3 in), this fritillary is relatively small. It has bright orange uppersides (yellow in females) and thinner black markings than most fritillaries.