Anisostena prompta is a species of beetle of the family Chrysomelidae. It is found in Argentina, Brazil (Bahia, Minas Gerais, Matto Grosso, São Paulo), Colombia and Paraguay.
Adults reach a length of about 4.1-4.7 mm. Subspecies prompta has a black head and an orange-red pronotum with black markings. The elytron is also orange-red with black vittae. Subspecies fasciata also has a black head, but the pronotum is yellow with black markings and the elytron is black with yellow vittae.
This species has been found feeding on Panicum leucophaeum.