The present study was designed to compare the linear and non-linear methods used to check the com-pliance of the experimental data corresponding to the isotherm models (Langmuir, Freundlich, andRedlich–Peterson) and kinetics equations (pseudo-first order and pseudo-second order). In this con-text, adsorption experiments were carried out to remove an anionic dye, Remazol Brillant Yellow 3GL(RBY), from its aqueous solutions using a commercial activated carbon as a sorbent. The effects of contacttime, initial RBY concentration, and temperature onto adsorbed amount were investigated. The amountof dye adsorbed increased with increased adsorption time and the adsorption equilibrium was attainedafter 240 min. The amount of dye adsorbed enhanced with increased temperature, suggesting that theadsorption process is endothermic. The experimental data was analyzed using the Langmuir, Freundlich,and Redlich–Peterson isotherm equations in order to predict adsorption isotherm. It was determined thatthe isotherm data were fitted to the Langmuir and Redlich–Peterson isotherms. The adsorption processwas also found to follow a pseudo second-order kinetic model. According to the kinetic and isothermdata, it was found that the determination coefficients obtained from linear method were higher thanthose obtained from non-linear method.