The adsorption of benzene, toluene, and o-xylene (BTX) in monocomponent and multicomponent aqueous solutions onto activated carbon was studied in a batch reactor at 23 degrees C for wastewater reuse. The kinetics and thermodynamic equilibrium parameters were obtained for all compounds, where the competitiveness for the active site of adsorption was investigated. The results showed that the order of monocomponent adsorption of these three contaminants is o-xylene > toluene > benzene, and in the multicomponent mixture o-xylene is the most competitive contaminant for the active site of adsorption. The adsorption kinetics were fitted to the homogeneous diffusion model, giving linear correlation coefficients higher than 0.96. The Langmuir isotherm provided the best fit with the monocomponent experimental data. In this study, the multicomponent mixture isotherms were obtained and compared to the models found in the literature.