The chemical composition of five Lamiaceae species essential oils, isolated by hydrodistillation, was analyzed by gas chromatography–mass spectrometry (GC-MS). Significant variation of essential oil composition was observed between species. T. capitatus and L. multifida were distinguished by high amounts of carvacrol (75.6 and 87.5%). Camphor (16.7%), α-pinene (13.6%) and 1.8-cineole (13.9%) were the main constituents of T. algeriensis essential oils, while the dominant compounds in L. stoechas were fenchone (59.1%) and camphor (23.7%). The highest amount of 1.8 cineole (51.6% and 32.5% for var.typicus and var. troglodytorum, respectively) was detected in Rosmarinus officinalis essential oil. Essential oils were assessed for their antioxidant capacity (DPPH, carotene bleaching test, Ferrous Ion-Chelating Ability Assay). The level of antioxidant activity among species was linked to that of their essential oil composition. The best activity was observed for essential oils characterized by the highest carvacrol content.