Tetramolopium arenarium is a rare species of flowering plant in the aster family known by the common name Maui tetramolopium. It is endemic to Hawaii, where it is known only from the island of Hawaii. It is extirpated from Maui. It is threatened by the degradation of its habitat. It is a federally listed endangered species of the United States. Threats to this species include habitat destruction and degradation by feral ungulates such as pigs, and competition from introduced species of plants such as fountain grass.