The study investigated the adsorption properties of celecoxib from acid-digested waste leather (ADCL) under various physicochemical conditions. The batch method was used to assess the effects of particle size, adsorbent dose, pH, temperature, initial concentration, and contact time. Results showed that the smallest particles, with the largest surface area, exhibited the highest adsorption capacity. Celecoxib exhibited 90.85% adsorption at pH 2, and the isotherm model demonstrated its adsorption behavior at different temperatures. Adsorption occurred at a pH of 2, with the amount of celecoxib adsorbed depending on the dose, contact time, and its initial concentration. The pseudo-second-order kinetics classified the process as physicochemical adsorption, and the results were supported by FT-IR, SEM data, XRD spectra, and thermodynamic analysis.