Dyes and pigments are environmental concerns because of their nonbiodegradability and toxicity. Many methods have been employed to remove dyes from aqueous solution, and adsorption is considered superior to other techniques. Activated carbon is one of the most widely used adsorbents for this application. In this study, activated carbon was prepared from low cost and locally available cherry stones using phosphoric acid with microwave preparation. Disperse yellow 211 was used as the adsorbate because of its common use in the textile industry. The surface properties of this new adsorbent were characterized by infrared spectroscopy, Brunauer-Emmett-Teller measurements, and scanning electron microscopy. The novel activated carbon material was employed for the removal of disperse yellow 211 from aqueous solution at various contact times, pH values, and solution temperatures. The optimum pH was 11. The surface area and micropore volume of the activated carbon were 1998 m²/g and 0.937 cm³/g, respectively. Adsorption equilibrium measurements were treated with Langmuir, Freundlich, and Temkin isotherm models and model parameters were determined. Pseudo-first-order and pseudo-second-order equations were fitted to the kinetic data, and the rate constants were evaluated. The kinetics followed a pseudo-second-order equation.