Medicinal and aromatic plants play a pivotal role in traditional and modern medicine due to their rich secondary metabolite content and associated therapeutic properties. This study investigates the phytochemical composition and antioxidant activity of aqueous and ethanolic extracts of Mentha spicata L. (spearmint) leaves and stems, collected from Tiaret region of Algeria. Results revealed that leaves exhibited significantly higher polyphenol and tannin concentrations than stems, irrespective of the solvent. Ethanolic extracts generally demonstrated greater efficiency in extracting polyphenols and flavonoids, with the highest flavonoid content observed in ethanolic leaf extracts (159.74 mg QE/g). Conversely, aqueous extracts were more effective in extracting tannins, with leaves containing 27.07 mg CE/g. Antioxidant activity, measured as IC₅₀ values, showed a strong correlation with the phytochemical content. Ethanolic extracts of the leaves exhibited the highest antioxidant potential, surpassing both stem extracts and their aqueous counterparts. These findings highlight M. spicata as a promising natural source of bioactive compounds for applications in the therapeutic, food, and cosmetic industries. Furthermore, they emphasize the importance of targeted extraction strategies to optimize the utilization of its bioactive potential, thereby contributing to eco-friendly innovations and biodiversity conservation.