A newly recorded Lithocarpus (Fagaceae) species for the flora of Vietnam, namely Lithocarpus encleisocarpus (Korth.) A.Camus was reported in this study. This species is most morphologically similar to L. dahuoaiensis Ngoc & L.V. Dung in having a completely entire leaf margin, solitary cupule, long stalks of fruits, deeply cup-shaped or turbinate cupules, with several horizontal filiform lines, but it differs from the latter by having cupules almost completely covering the nut, surface of the cupule densely fulvous tomentose by stellate hairs, secondary veins 8-10 pairs. This study provides the phylogenetic relationship of L. encleisocarpus with its close species based on genome-wide SNPs. Taxonomic treatment, photographs, information on distribution and habitat, and the GenBank accession number for DNA barcodes of the species are also provided.