The essential oil of Cyclospermum leptophyllum (Pers.) Sprague ex Britton and P. Wilson syn. Apium leptophyllum (Pers.) F. Muell. Ex Benth., family Apiaceae (Umbellifereae), was analysed by GC and GC-MS. The essential oil showed the presence of thymohydroquinone dimethyl ether (50.7%), thymol methyl ether (11.2%), γ-terpinene (10.4%), p-cymene (9.5%) and carvacrol methyl ether (5.9%), along with trans-ocimene, β-pinene, germacrene D, cumin aldehyde, α-humulene, β-myrcene, sabinene, limonene, β-phellandrene, caryophyllene oxide, α-pinene and α-thujene as minor constituents. To the best of our knowledge, this is the first study of the essential oil composition of C. leptophyllum collected from India.