Artemisia herba-alba Asso., Asteraceae, is widely used in Morrocan folk medicine for the treatment of different health disorders. However, no scientific or medical studies were carried out to assess the cytotoxicity of A. herba-alba essential oil against cancer cell lines. In this study, eighteen volatile compounds were identified by GC-MS analysis of the essential oil obtained from the plant's aerial parts. The main volatile constituent in A. herba-alba was found to be a monoterpene, Verbenol, contributing to about 22% of the total volatile components. The essential oil showed significant antiproliferative activity against the acute lymphoblastic leukaemia (CEM) cell line, with 3 µg/mL as IC50 value. The anticancer bioactivity of Moroccan A. herba-alba essential oil is described here for the first time.