Polyaniline/cerium oxide (PANI/CeO2) composites were prepared and characterized by XRD, FT-IR, nitrogen adsorption/desorption isotherms and TEM techniques. The PANI/CeO2 composites were used for removal of Remazol Red (RB-133) from aqueous solution. The adsorption behaviour of dye was studied at different experimental conditions of solution pH and reaction temperature. The adsorption isotherm studies were carried out using Langmuir and Freundlich models, of which Freundlich model was found more suitable. Pseudo-second-order model fitted well with good agreement with the experimental values of qe (equilibrium adsorption capacity). Thermodynamic parameters for the adsorption system were calculated and suggested that the adsorption process is spontaneous, exothermic and marked with an increase in randomness at the solid–liquid interface.