Ptychochromis inornatus, n. sp., is described from the Ankofia basin, northwestern Madagascar. The new species is diagnosed from congeners by the absence of large, black midlateral blotches or bars, and the presence of only two rows of teeth on the second pharyngobranchial toothplate, a robust uncinate process of the first epibranchial bone that is at least twice the diameter of the anterior arm, anterior chest scales that are reduced in size and embedded, a rounded and truncate postero-dorsal margin on the supraoccipital crest, and red fin coloration in life. Ptychochromis inornatus is endemic to the Ankofia drainage basin, with a geographic range extending from the Anjingo River northward to Lake Andrapongy and its surrounding drainages. Intrageneric variation within Ptychochromis is also discussed and comparisons made to the new species.