Bruggmannia >chapadensis sp. nov. is described and illustrated based on characters of the larva, pupa and adults of both sexes, from specimens collected in Cerrado areas of Parque Nacional da Chapada dos Guimarães, state of Mato Grosso, Brazil. The new species is characterized by tarsal claws bent at distal 1/3; well-developed empodia, not reaching the bend in claws; cerci rounded; hipoproct shorter than cerci; aedeagus with globose apex; gonostylus semicircular; ovipositor protrusible about 1.4 times longer than sternite 7; pupal antennal bases enlarged, conical, upper facial horns semicircular; prothoracic spiracle short, abdominal segments 2–8 with one row of dorsal spines; larval terminal segment elongate, with four setose terminal papillae. This new species was collected from lenticular leaf galls of Guapirapernambucensis (Casar.) Lundell (Nyctaginaceae). This is the first record of Bruggmannia galls on this plant species. In Brazil, 13 species of Bruggmannia were previously known, none recorded from Mato Grosso.