The adsorption behavior of Allura red (E129) from aqueous solutions onto activated carbon was successfully investigated. All factors affecting the adsorption process were carefully studied and the conditions were optimized. Adsorption of E129 onto activated carbon was found to increase by decreasing the mass of activated carbon, pH and ionic strength of the solution and by increasing temperature. Under the optimum conditions, the maximum adsorption capacity of activated carbon for E129 dye was 72.85 mg.g -1 . Three adsorption isotherm models; Langmuir, Freundlich and Temkin model were investigated regarding E129 adsorption onto activated carbon. The models' parameters KL, qm, R2, and (n) were determined and found to be 0.0222, 72.85 mg.g -1 , 0.9057-0.9984, and 0.992, respectively. Moreover, pseudo first-order and pseudo second-order kinetic models were applied to the adsorption data. The obtained data from adsorption isotherms, kinetic models, and thermodynamic parameters (the free energy change, enthalpy and entropy) indicated that E129 adsorption is spontaneous exothermic heterogeneous adsorption. Furthermore, the results showed that E129 adsorption onto activated carbon obeyed both Freundlich isotherm and pseudo second-order kinetic models.