This research studied the effect of copper oxide nanoparticles (CuO NPs) on the emission and nonlinear optical properties of three dyes: rhodamine B, methylene blue, and saffron dye.The nonlinear optical response of Rhodamine B dye shows the highest nonlinear response at the impact of the 532 nm laser, where the nonlinear refractive index is large, and at the 405 nm laser, the addition of copper oxide nanoparticles, in contrast to 532 and 650 nm. Methylene blue dye shows the highest nonlinear response at 650 nm, which coincides with the absorption maximum of the dye. This dye absorbs red more effectively, which explains the increased nonlinear refraction. Interestingly, the addition of copper oxide nanoparticles increased the nonlinear response at all wavelengths. Saffron dye showed the highest nonlinear response at 405 nm laser impact, where the nonlinear refractive index is good and decreases at longer lengths.