Euphorbia parvicyathophora is a species of plant in the family Euphorbiaceae. It is endemic to South-West Madagascar. The Euphorbia parvicyathophora typically lives in an environment that is of rocky material; particularly, limestone is its primary locale of habitation. Euphorbia parvicyathophora grows within the soil pockets of cavernous limestone along the southern bank of the Fiherenana river, a river in the southern part of Madagascar, which flows to the Indian Ocean. Euphorbia parvicyathophora is threatened by habitat loss.