This study explores the fern diversity of the Fifa Mountains in Jazan Region, Saudi Arabia, using an integrative approach that combines morphology, DNA barcoding, and GC-MS profiling. Six fern species (Actiniopteris radiata, A. semiflabellata, Adiantum capillus-veneris, A. incisum, Cheilanthes viridis, C. coriacea, and Asplenium praemorsum) and one fern-like species (Selaginella yemensis) were identified. DNA barcoding using ITS and rbcL independently, confirmed most morphological identifications, while correcting Asplenium aethiopicum to A. praemorsum. However, limitations in the databases restricted resolution for A. semiflabellata (ITS) and C. cf. coriacea (partial rbcL match), underscoring the urgent need for additional fern sequences in GenBank. Among the markers tested, rbcL provided higher resolution than ITS. GC-MS profiling revealed a diverse array of secondary metabolites, with both similarities and distinctions across species, reflecting ecological adaptations and supporting taxonomic relationships. These findings provide the first combined molecular and chemical dataset for ferns in this arid region, demonstrate the complementarity of morphological, molecular, and chemical approaches, and highlight the critical need to enrich barcode databases for underrepresented fern taxa.