A multilayer adsorption model is applied to interpret the experimental data for the adsorption of kaolinite clay particles at the oil-water interface of an oil-in-water emulsion. The results show that the equilibrium constant for the formation of the first adsorption layer is much larger than that for the second and subsequent layers. The desorption process is characterized by hysteresis. To obtain a stable solids-stabilized oil-in-water emulsion, it is necessary for the droplets to be covered by at least a complete monolayer of particles. Otherwise, the oil droplets can coalesce quite easily.