In this paper, we described a new species of Grigiotermes, G. piassava sp. n., from the Brazilian Atlantic Forest. The imago and worker caste are described, including the gut morphology. The inclusion of the new species in Grigiotermes was based on morphological and DNA data. Apparently, the distribution of the species is limited to the northern region of the Atlantic Forest, located above the São Francisco River, which is considered one of the most threatened sectors of the biome.