Lavandula dentata L., popularly known as lavender, is considered to be a medicinal plant that has great economic potential. The aims of the present study were to characterize the morphology of L. dentata grown in Paraíba do Sul, Rio de Janeiro, Brazil and determine the content and chemical composition of its essential oil. Morphology of the plant was determined using the optical microscope, digital calliper and measuring tape. The fresh plant material characteristics consisting of the branches, leaves, and inflorescence were described. The essential oil was obtained by hydrodistillation and analyses chemical characteristics were performed by gas chromatography (GC) and gas chromatography coupled to mass spectrometry (GC/MS). Our study shows a large number of non-glandular trichomes were identified, as well as two types of glandular trichomes, including capitate and peltate glandular trichomes. This work achieved high essential oil content which were related to vegetable biomass. The major constituents found in the essential oil from L. dentata were the monoterpenes: eucalyptol - 1.8 cineol (39.43%), camphor (20.11%), and fenchone (18.40%). Thus, it was possible to characterize the morphology and chemical composition of L. dentata.