Introduction: The ethyl acetate fraction of the Saudi Lavandula coronopifolia Poir has been previously reported to have hepatoprotective activity against ethanol-induced oxidative stress. The aim of the current study was to investigate the chemical composition, cytotoxic effect, and antioxidant activities of ethyl acetate fraction of the aerial parts of Saudi L. coronopifolia Poir. Methods: Air dried aerial parts of L. coronopifolia were extracted using 90% ethyl alcohol. The dried extract was suspended in water, defatted with light petroleum and then fractionated with ethyl acetate. The ethyl acetate fraction was subjected to ultra performance liquid chromatography-tandem mass spectrometeric (UPLC-ESI/MS/MS) analysis in a negative ionization mode. The antioxidant activity of the fraction was determined using free radical 2,2-diphyenyl-picrylhydrazyl (DPPH) scavenging assay and its cytotoxic effect against HepG- 2 (human hepatocarcinoma) and MCF-7 (human breast carcinoma) cells were determined using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) tetrazolium (MTT) cell viability assay. Results: The major components of the ethyl acetate fraction included carvacrol-O-diglucoside, (34.98%) and trihydroxy ursolic acid (12.07%). Moreover, the DPPH radical scavenging activity of ethyl acetate fraction was measured. The ethyl acetate fraction revealed an antioxidant potential with EC 17.8 ± 1.3 µg/mL. Additionally, the ethyl acetate fraction showed cytotoxic activity against HepG-2 and MCF-7 cells with IC 50 =29.3 ± 0.9 µg/mL and 14.6 ± 0.3 µg/mL, respectively. Conclusion: The ethyl acetate fraction of the Saudi L. coronopifolia has antioxidant activity and also cytotoxic activity against breast and liver cancer cells. 50