The study assessed the floristic diversity and analysed the structure of plant groups in the Pénéssoulou Forest Reserve (PFR). For this purpose, 234 plots of 50 m × 20 m each were installed in delimited floristically homogenous stands. An individualization of the different plant groups of the PFR was carried out using non-metric multidimensional scaling. Alpha diversity indices were used to evaluate the floristic diversity of the plant communities. Dendrometric parameters and size class structures of diameter and height were performed to understand the conservation status of the identified plant communities. Four plant communities was identified: G1 corresponded to woodlands and savannah woodlands with Vitellaria paradoxa and Uapaca togoensis as characteristic species, and including 81 woody species; G2 corresponded to forest gallery, dominated by Anogeissus leiocarpa and Cola gigantea and including 100 woody species; G3 corresponding to tree and shrub savannahs with Vitellaria paradoxa and Parinari curatellifolia as characteristic species, and including 64 woody species; and G4 corresponded to Anogeissus leiocarpa - Lonchocarpus sericeus dry forest that included 75 woody species. The dendrometric parameters varied significantly from a plant group to another (P-value < 0.05). The distribution of tree diameters was in an inverted «J» shape, characteristic of multi-species stands. As for the structures in height, they reflected a rarity of higher individuals (>20 m). The results showed an acceptable state of conservation and a good natural regeneration capacity of the forest, which must be improved through the implementation of a forest management plan.