Udea octosignalis is a moth in the Crambidae family. It was described by Hulst in 1886. It is found in North America, where it has been recorded from California and Texas. The wingspan is about 20 mm. The forewings are light ochreous, the costal area and markings buff. The basal line is rounded and the outer line is sinuous, both without dentations. There is faint subterminal fuscous shading and the marginal line is fine and buff. The hindwings are white, faintly ochreous outwardly and the marginal line is fine and brownish.