The adsolubilization of 2-naphthol by surfactant mixtures of an anionic surfactant, sodium dodecyl sulfate, and a nonionic surfactant, hexaoxycthylenedodecyl ether on alumina was investigated. In a single-surfactant system, only the anionic surfactant was found to show an appreciable adsolubilization. In the mixed-surfactant system, the adsolubilization grew with an increase in the total amount of adsorbed surfactant, whereas the adsolubilization became greater with an increase in the anionic surfactant content in the initial mixtures. On the other hand, the ratios of adsolubilized amount to surfactant. adsorbed amount became smaller when the anionic surfactant content in the initial mixtures increased. This behavior is attributed to the properties of the mixed-surfactant adsorbed layer at the alumina-water interface.