As a part of prospecting bioactive molecules from natural resources, the phytochemical composition and antioxidant properties of extracts of leaves and berries oilcake of Pistacia lentiscus L., collected from two sites (Mechat and Bordj-Ali) in the northeast region of Algeria, were investigated. Dried leaves and berries oilcake obtained after removing the oily part by mean of Soxhlet apparatus were macerated in methanol in order to recover their respective active extracts. The phytochemical content analysis showed that lentisk leaves of both sites were relatively rich in polyphenols, flavonoids, flavonols and proanthocyanidins. The phytochemical content of berries oilcake extract was lower than that of leaves, yet, samples of Bordj-Ali displayed higher values for all assayed phytochemicals compared to those of Mechat. The P. lentiscus leaves extract exhibited a strong radical-scavenging activity (IC50 = 10.46 µg/mL) against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and a substantial inhibitory activity against H2O2 free radicals (20.23 - 25.92%). Furthermore, these extracts displayed a very strong reducing power (EC50 = 28.08 µg/mL) and total antioxidant capacity (104.07 - 159.39 mg EAA/g DW). The observed results correlated positively with total phytochemical content strongly plead in favor of valorization of this wild plant as a potential natural source of active biomolecules for food, cosmetics, and medicinal industry sectors.