As a part of a taxonomic update of the family Convolvulaceae Juss. for Guayana Shield, the species Jacquemontia austiniana J.R.Grande sp. nov., is described and illustrated as new to science. This species is characterized by its linear-subulate bract, ovate-lanceolate external sepals, conspicuously acuminate, villose, with the margins ciliate, and a relatively large and infundibuliform corolla. To date, this is the only species of Jacquemontia Choisy endemic to the Guayana Shield; its relationships within the genus are still to be elucidated.