Abstract The chemical composition of the essential oils obtained from the galls and the aerial parts of Pistacia lentiscus L. (Anacardiaceae) was analyzed by GC/MS. Among the 58 constituents identified (representing 82.8% of the oil composition) sesquiterpene hydrocarbons predominated (ca. 47%), β-caryophyllene (13-1%), δ-cadinene (8.1%) and Germacrene D (6.8%) being the major components. Although galls and oils of the aerial parts were similar from a qualitative viewpoint, the latter oil was somewhat more complex (73 components identified, accounting for 85.4% of the oil) and the monoterpene hydrocarbons fraction (ca. 35%) was now dominant in the oil, α-pinene (13.0%), β-caryophyllene (6.9%), limonene and β-phellandrene (5.4%), β-pinene (4.9%) and p-cymene (4.7%) being the main components.