The purpose of the current work is to use Tabernaemontana divaricata green leaf extract to experimentally determine the biosorptive properties of produced zinc oxide nanoparticles (ZnO-Nps). SEM, XRD, and FTIR analysis were used to evaluate synthesized ZnO-Nps. The size of the resulting nanoparticle is 189 nm. The process variables such as agitation time, initial CR dye concentration, pH, and dosage of zinc oxide nanoparticles along with temperature were carried out and compared by response surface methodology (RSM). At the optimized parameter conditions, the adsorption of dye was studied from Isotherms, Kinetics, and Thermodynamics, respectively. At the optimized parameter conditions, maximum removal of CR dye that occurred is 93.1%. In comparison to various isotherm and kinetic models, it was discovered that the Langmuir model and pseudo second order kinetics best suited the data. The results of thermodynamic studies give exothermic nature, and thermodynamically feasible nature of adsorption.