Dispersion characteristics of silicon nitride, silicon carbide, alumina, aluminum nitride and yttria powders in aqueous solutions of anionic and cationic polyelectrolytes were studied by measuring particle size distribution using a gravity sedimentation technique. The influence of polyelectrolyte concentration and suspension pH on the dispersion was examined. All powders examined in this study could be well dispersed in the presence of either cationic or anionic polyelectrolyte by adjusting the dispersion pH to at least 2.5 pH units away from the effective pH(iep) (iep=isoelectric point) of the powder-polyelectrolyte system. The dispersion characteristics of these powders in the presence of polyelectrolytes are explained in terms of interfacial interactions in the powder-polyelectrolyte systems. These interactions between the powder and polyelectrolytes as a function of suspension pH, and possible mechanisms leading to the stability of particles in a dispersion, are discussed.