Platysphinx piabilis is a moth of the family Sphingidae first described by William Lucas Distant in 1897. It is known from savanna and other open habitats in southern and eastern Africa. The length of the forewings is 58–62 mm for males and 60–65 mm for females and the wingspan is 109–132 mm. There are red spots on the hindwing, which are evenly distributed and not arranged in regular bands. The forewing of the females is broader, less acuminate, darker and more reddish than in males. The hindwings are more heavily spotted with red. It is separable from Platysphinx phyllis and Platysphinx stigmatica only convincingly by examining the genitalia.