The number of vascular plant species known to occur in Gabon rises quickly due to renewed inventory activities. Here, two genera (Alloteropsis, Entolasia), twelve species and one variety of grasses are recorded from Gabon for the first time (Alloteropsis paniculata, Cenchrus echinatus, Elionurus platypus, Entolasia olivacea, Eragrostis patens, Hyparrhenia diplandra var. mutica, Leersia triandra, Loudetia annua, Oryza longistaminata, Puelia schumanniana, Rottboellia purpurascens, Sacciolepis africana, Setaria geminata), while information on three erroneous species reports is provided. This brings the total number of grass species known to occur in Gabon to 188. Finally, new records of three rare species (Elionurus hensii, Guaduella macrostachys, Paratheria prostrata) are discussed.