Lebanon's well-documented history in grape cultivation and winemaking dates back millennia, intertwining with its cultural heritage and landscape. However, until recent years, Lebanon's grapevine genetic resources have received limited attention. This study presents a comprehensive exploration and characterization of Lebanese local underexploited resources, beginning with the collection of 276 accessions throughout the country, with an emphasis on old/abandoned vines and vineyards. Molecular analyses were conducted on these accessions; 22 nuclear simple sequence repeat (SSR) markers and 3 chloroplastic SSR markers were used to assess their genetic diversity. A total of 102 distinct genotypes were identified, 63 of which exhibited original genetic signatures previously undocumented in international databases, highlighting the unique genetic richness of Lebanon's grapevine germplasm. Subsequent morphological characterization using a set of descriptors developed by International Organization of Grapevine and Wine (OIV) provided valuable insights into the phenotypic traits of these newly found grape cultivars. Parentage analysis facilitated the elucidation of genetic relationships among the accessions and the construction of genetic pedigrees. Comparative analysis with a set of cultivars of very diverse geographical origin positioned Lebanese accessions within the Eastern Mediterranean group, suggesting shared genetic affinities with regional counterparts. Lebanon's grapevine genetic resources are key for conservation, breeding, and future viticulture research. Preserving these resources protects the nation's heritage while fostering innovation and resilience in winemaking amid environmental changes.