The mechanism of palladium extraction from aqueous ammonium chloride solutions with dihexyl sulfide in toluene was investigated at 303 K from the viewpoints of extraction equilibrium and kinetics. The result of a loading test suggests that palladium is extracted as a 1:2 metal-reagent complex. The concentration dependencies of the reactant species were examined using a stirred transfer cell with a constant interfacial area to investigate the extraction rate mechanism. The observed extraction rate was reasonably explained in terms of a simple reaction scheme involving complex formation between the intermediate complex adsorbed at the interface and a free extractant molecule dissolved in the aqueous phase as the rate-determining step.