The effects of an anionic and a nonionic surfactant on aqueous dispersions of three types of iron oxides were investigated by particle size and zeta potential measurements. Iron oxide particles were suspended in an aqueous iron (III) chloride solution to render their surface positively charged. The so prepared sols were then flocculated by the addition of a small amount of sodium lauryl sulfate. The flocs of iron oxide could be redispersed by further addition of sodium lauryl sulfate or by nonionic surfactants. The flocculation and the redispersion processes can be explained in terms of a “two-fold adsorption layer” mechanism of the surfactants. The concentrations of the nonionic surfactants needed to achieve redispersion, decreased with an increase in the ethylene oxide chain length. The sols of needle-like iron oxide particles required lower concentrations of surfactants for flocculation and redispersion than those containing cubic particles.