We describe Oryzias dopingdopingensis, a new species of ricefish, from Doping-doping River, a river in Malili in central Sulawesi, Indonesia. The new riverine species is distinguished from lacustrine congeners in Malili Lakes by a combination of 33–36 scales along the lateral midline and body depths of 20.3–25.5% standard length (SL). Oryzias dopingdopingensis, new species, is also distinguished from all other Sulawesi Oryzias by a combination of 8–9 dorsal-fin rays, caudal peduncle depths of 10.2–11.4% SL, eye diameters of 8.5–9.9% SL, and maximum SL up to 35.8 mm. In breeding males, 5–8 black blotches or bars appear along the lateral midline. Analyses of mitochondrial ND2 sequences revealed that O. dopingdopingensis, new species, carry distinct haplotypes from those of the Malili lacustrine species, suggesting no hybridization between them, although Doping-doping River shares an estuarine region with the Malili Lake system. Instead, O. dopingdopingensis, new species, is in a monophyletic group with O. sarasinorum and O. eversi in western Sulawesi. However, unlike these two pelvic brooders, we observed that females of O. dopingdopingensis, new species, deposit eggs soon after spawning and exhibit no maternal care.