We describe a new species of treefrog of the Scinax ruber clade related to Scinax fuscomarginatus from southwest of the state of Goiás in central Brazil. The new species is characterized by its small size (snout–vent length of males, 15.9–18.6 mm; females, 18.1–18.7 mm), very slender body, a snout that is strongly acute in lateral view and subelliptical in dorsal view, two lateral broad blackish stripes from the posterior corner of the eye to inguinal region, reduced toe webbing, and advertisement calls that are a single pulsed note with a pulse period of 2–13 ms and a dominant frequency of 2.51–5.95 kHz. Vocalizations of the new species and S. fuscomarginatus, Scinax parkeri, Scinax squalirostris, and Scinax wandae are provided and discussed.