​In the current study, the compositions of the essential oil obtained from leaves of Ocimum basilicum ‘Cinnamon’grown in Jordan in a greenhouse was analysed. The antitumor activity of the essential oil was examined against three different cancer cell lines including MDA-MB-231, MCF7 and U-87 MG. The hydrodistillation method was used to extract the essential oil from Ocimum basilicum and the chemical components were analyzed and identified using gas chromatography-mass spectroscopy. The dry weight yield of essential oil was 0.50%(w/w). Thirty-one components representing 97.80% of the essential oil were identified. The main chemical components revealed the presence of linalool, eugenol, eucalyptol, hinesol, trans-α-bergamotene and γ-cadinene as the major constituents. In conclusion, the essential oil extracted from greenhouse cultivated Ocimum basilicum European chemotype showed potent antitumor activity.