In this study, nickel cobaltite (NC) nanoparticles were created using the sol-gel process and used as an adsorbent to adsorb methyl green dye (MG) from aqueous solutions. The adequate preparation of nickel cobaltite nanoparticles was verified using FT-IR, SEM, and X-ray diffraction (XRD) studies. The crystalline particle size of NC nanoparticles was 10.53 nm. The effects of a number of experimental variables, such as temperature, adsorbent dosage, and contact time, were examined. The optimal contact time and adsorbent dosage were 120 minutes and 4.5 mg/L, respectively. Four kinetic models—an intraparticle diffusion, a pseudo-first-order equation, a pseudo-second-order equation, and the Boyd equation—were employed to monitor the adsorption process. Modeling of the experimental data showed that the pseudo-second-order model accurately captured the adsorption kinetics due to the high value of the correlation coefficients (R²). MG dye is gradually adsorbed to the NC nanoparticles through boundary layer diffusion and intraparticle diffusion. The results of the thermodynamic analysis showed that the MG dye adsorption was endothermic and a nonspontaneous phyisorption process.