Various phytotherapeutic compounds with hypoglycemic properties offer a promising avenue to combat diabetes and its associated complications. This study was carried out to investigate the in vivo and in vitro antidiabetic activity and bioactive compounds of Salvia verbenaca, Ferula vesceritensis Coss & Dur., and Myrtus communis L., which are used in Algerian traditional medicine. The in vivo antidiabetic assays of infusion extracts of the three plants at 100 and 500 mg/kg b.w, were performed using a hypoglycemic study in normal mice, an oral glucose tolerance test, and streptozotocin-induced diabetic mice. The α-amylase inhibitory test was used to determine the in vitro antidiabetic activity. Phytochemical composition and bioactive profiling were determined using HPLC analysis. The findings indicated a general agreement between in vivo and in vitro antidiabetic effects, rather than a direct quantitative correlation. In the in vivo antidiabetic activities, the infusion extract of F. vesceritensis displayed significantly (P<0.05) higher potency in reducing glycemia, glucose load–induced hyperglycemia, and in alleviating streptozotocin-induced diabetes, highlighting its potential as a source of bioactive compounds for therapeutic applications, with effects comparable to or higher than metformin under the tested conditions. S. verbenaca infusion extract showed a comparable blood glucose reduction to the reference drug. Similar findings were obtained in the α-amylase inhibitory test, where the infusion extract of F. vesceritensis showed strong inhibitory activity, while S. verbenaca also exhibited comparable inhibitory effects relative to the reference under the tested conditions. The phytochemical analysis revealed the presence of rutin and kaempferol in F. vesceritensis and S. verbenacainfusion extracts, and their absence in M. communis infusion extract, which may explain their observed bioactivity and supports their relevance as natural products with antidiabetic potential. However, further in vivo and clinical studies are required to confirm these findings and their translational relevance.