Essential oil from the leaves of Pistacia lentiscus L. growing in the Oran region in the west of Algeria was obtained by hydrodistillation with a 1.26 % yield on a dry weight basis. Spectrophotometric analyses were employed to highlight the scavenger capacity of this oil using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test. Twenty compounds were identified by GC and CG/MS analyses, and the main part of the compounds of the oil was terpinene-4-ol (41.24%) and α-terpineol (7.31%), α-pinene (9.48%), limonene (09.11%), β-myrcene (10.5%), p-cymene (8.67%) and α-phellandrene (2.20%), β-caryophyllene (12.62%) as major compounds. The DPPH test shows that Pistacia lentiscus essential oil possesses antiradical activity. A linear correlation (correlation coefficient R 2 = 0.995, P < 0.001) was found between the reduction of DPPH stable free radical and the concentration of Pistacia lentiscus essential oil.