Lasianthus is a genus of flowering plants in the family Rubiaceae. They are tropical subshrubs, shrubs, or rarely, small trees. They inhabit the understory of primary forests. None of them are known to have any use. Dried specimens of Lasianthus often shed their flowers and fruit. For this reason, misidentification is common, even in herbaria. The name Lasianthus has been misapplied to Lisianthius (also spelled as "Lisianthus" or "Lisyanthus"), a genus in Gentianaceae. Lasianthus alatus Aublet is a misspelling of Lisyanthus alatus Aublet, a species now placed in Chelonanthus.