A large number of industries such as exploration, oil storage, refineries, and transportation produce oily wastewater, which poses a terrible threat to our ecological environment. In oily wastewater, the oil concentration lies in the range of 100–1000 (mg/l) along with different contaminants such as oil droplets, hydrocarbons, and dissolved and suspended solids. Different conventional methods like adsorption, flocculation, coagulation, and membrane separation cannot be used to reduce the oil concentration to an acceptable level. Among them, porous ceramic microfiltration (MF) membranes have enormous potential based on their high separation efficiency along with higher chemical, thermal, and mechanical stability. These membranes are generally prepared with costly synthetic powders like alumina, titania, zirconia, silicon carbide, silicon nitride, etc. Recently, mullite and mullite-alumina-based membranes, have attracted much attention as low-cost alternatives. Thermal features of some of the cheaper raw materials like kaolin, silica, etc. used in their fabrication also provide an added advantage for sintering at lower temperatures compared to the synthetic ceramic powders. This chapter deals with the potential of mullite and mullite-alumina membranes in oily wastewater treatment.