In this work, a polyaniline/iron oxide (PANIIO) composite was prepared and evaluated for its amido black 10B (AB10B) dye adsorption characteristics from aqueous solution. Adsorption equilibrium kinetic and thermodynamic experiments of AB10B onto PANIIO were studied in a batch system. The effects of solution pH, initial dye concentration, contact time, and temperature on the adsorption capacity of PANIIO for AB10B have been investigated. The pseudofirst-order and pseudosecond-order kinetic models were used to describe the kinetic data. It was found that adsorption kinetics followed the pseudosecond-order kinetic model at all of the studied temperatures. The Langmuir and Freundlich adsorption models were used for the mathematical description of adsorption equilibrium data, and the best fit was obtained using the Freundlich isotherm with an R(2) value of 0.9948. The change of Gibbs energy, enthalpy, and entropy of adsorption was also evaluated for the adsorption of AB10B onto PANIIO.