A new species, Triodia turkmenica Knyazev, sp.n. from Turkmenistan, is described. A detailed description of the external characteristics of the male and female, as well as the structure of the genitalia, is provided. The new species is closely related to Triodia laetus (Staudinger, 1877) but is distinguished by its smaller size, lighter and more mottled coloring. There is also an external similarity with Triodia amasinus (Herrich-Schäffer, [1852]) from which the new species differs well in the structure of the genitals. The female of the new species is similar to the female of Triodia sylvina (Linnaeus, 1761), but differs well from it in a strongly segmented wing pattern.