Lyonetia euryella is a moth in the Lyonetiidae family. It is known from the islands of Honshu, Kyushu and Yakushima in Japan. The wingspan is 8–10 mm. Adults are on wing from the beginning to the middle of May, from the middle of June to the beginning of July, from the end of July to the beginning of August and from the beginning of September to the beginning of October. There are four generations per year.