Abstract The chemical composition of the essential oil obtained from the aerial parts of Teucrium massiliense L. was analyzed by GC and GC/MS and the components identified were 34, mainly 3,7-dimethyloctan-2-one (15.2%), butyl 2-methylbutyrate (12.1%), linalool (10.6%), linalyl acetate (7.1%), zingiberene (4.7%), Î³-cadinene (4.1%). The anti-oxidant activity of the oil was evaluated by the DPPH test, where the oil showed an effect comparable to Trolox, and by lipid peroxidation test, where the activity of the oil was three time less effective than that of Trolox.