Tamarix tetragyna is a plant grows in Mediterranean area and some Arab countries. It possesses numerous medicinal values. Purpose of our study is to explore biological activity of tamarix tetragyna extracts of both leaves and stem with investigating their phytochemical composition. The investigated extracts’ phyto-constituent composition was determined using gas chromatographic-mass spectrometric method. In addition, in vitro cytoxicity activity versus cancer cell lines such MCF-7, HepG-2, HCT-116, and A-549 was examined by MTT assay method, together with exploring its apoptosis effect by flow cytometry and western blot analysis techniques. Moreover, some phytochemical compounds were identified, and in-silico evaluated against anticancer molecular targets. Plant extracts showed good cytotoxic activity against both A-549 and HCT-116 cancer cell lines. With an IC50 value of 23.90 µg/ml that led to apoptosis and G2/M-phase arrest in A-549 cells, cytotoxicity data demonstrate leaves’ extract effectiveness against these cells. Upon GC-MS analysis, it revealed presence of some bioactive components such as Stigmast-5-en-3-ol and 2-methoxy-4-vinyl phenol, which are known for their cytotoxic activity. Our findings suggest that methanolic extracts of Tamarix tetragyna parts may have potential therapeutic uses as anticancer against A-549 cells, which opens up further avenues for investigation into its industrial applications.