Aim: The aim of the study is to analyze the phytoconstituents and to determine the anticancer potential of Linum usitatissimum seed against Human cervical cancer cell line is the correct expansion (HeLa). Materials and Methods: The seeds of L. usitatissimum were extracted with methanol, ethyl acetate, and chloroform by cold maceration method. These extracts were subjected to qualitative phytochemical analysis, free-radical scavenging ability (1,1-diphenyl-2-picrylhydrazyl) assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and flow cytometric analysis for studying their cytotoxic and apoptotic effect on HeLa cell. Ethyl acetate extract of L. usitatissimum seeds was subjected to liquid chromatography–mass spectrometry (LC-MS)/MS analysis for identifying its phytoconstituents. Results: Qualitative analysis of the different extracts of the seed revealed the presence of flavonoids, terpenoids, alkaloids, saponins, glycosides, phenols, steroids, and anthraquinones. Free-radical scavenging activity of chloroform extract was found to be more than methanolic and ethyl acetate extracts. Further, methanol, ethyl acetate, and chloroform extracts exerted cytotoxic effect with an 50% inhibitory concentration value of 21 μg/ml, 17.5 μg/ml, and 20 μg/ml, respectively. Flow cytometric analysis revealed that the number of proapoptotic and late apoptotic cells were found to increase with the increasing concentration of seed extract. LC-MS/MS analysis of ethyl acetate extract revealed the presence of glabranine, protocatechuic acid-O-hexoside, and naringenin. Conclusion: The study demonstrated the anticancer effect of the seeds of L. usitatissimum , and the presence of glabranine and naringenin, well-known anticancer agents, is being reported for the first time in L. usitatissimum seed. The antioxidant and anticancer potential of the seed could be due to the presence of glabranine and naringenin.