The current study was undertaken in order to determine the chemical composition of the leaf essential oils of Lavandula dentata L. (Lamiaceae) cultivated in Tebessa (Algeria) and to evaluate its potential larvicidal activity against fourth instar larvae of Culiseta longiareolata Macquart and Culex pipiens L. (Diptera: Culicidae). The essential oil content of L. dentata leaves obtained by hydrodistillation was 1.18%dry weight. The chemical analysis performed by gas chromatography-mass spectrometry showed that this essential oil contained eight compounds. The major chemical constituents identified were a-terpinolene (51.13 %) and camphor (13.43 %). Bioassay test done following the World Health Organization standard protocol revealed that this essential oil exhibited larvicidal activity. The LC₅₀ and LC₉₀ values against fourth instar larvae were 77.09 and 104.45 ppm for Cs. longiareolata and 113.38 and 150.38 ppm for Cx. pipiens, respectively. The results proved the potential use of this natural product as an alternative to synthetic insecticides for controlling mosquitoes.