Mythimna obsoleta, the obscure wainscot, is a moth of the family Noctuidae. The species was first described by Jacob Hübner in 1803. It is found in Europe, from southern Fennoscandia to Spain, Italy and the Balkans, the European part of Russia, the Caucasus, Kazakhstan, Kyrgyzia, southern Siberia, Turkey, the Ural, Mongolia, the Russian Far East, the Korean Peninsula, China and Hokkaido and Honshu in Japan.