In this research, copper oxide nanoparticles (CuO-NPs) were biosynthesized through a simple, quick, and green manner by the exertion of okra (Abelmoschus esculentus) fruit extract as a stabilizer and reducing agent. TGA/DTA, UV–Vis, DRS, FTIR, XRD, BET, TEM, FESEM/EDX, and PSA analyses were used to characterize the CuO-NPs. The XRD analysis of CuO-NPs exhibited the monoclinic structure of crystallizes in a size of about 25 nm. The optical and surface characteristics of CuO-NPs were examined by the results of DRS and BET analyses, while their surface area was observed to be 5.6 m2/g. The absorption spectra of NPs revealed a peak at around 320 nm. In addition, as their FESEM/TEM/PSA images displayed their spherical shape in a size of about 20 nm. The effectiveness of CuO-NPs as a photocatalyst was examined by testing their ability to degrade various dyes under UV light. According to the outcomes after 210 min, the degradation percentages of Eriochrome black T (EBT), Rhodamine B (RhB), and Methylene blue (MB) dyes were approximately 88, 96, and 88%, respectively. The anticancer efficacy of CuO-NPs against the HeLa cancer cell line in 24, 48, and 72 h (IC50=1000, 500, and 250 μg/mL, respectively) was observed to be significant, whereas lower cytotoxic effects were induced on the normal fibroblast L929 cell line when compared to that of cancer cells. The viability of normal cells at a concentration of 1000 μg/mL was decreased to 74, 71, and 65% after 24, 48, and 72 h, respectively.