This review highlights recent advances in the development and use of eco-friendly polymeric membranes made from polymer blends for treating oily wastewater, a major source of environmental pollution. Among treatment options, membrane separation stands out because of its high efficiency and ability to selectively remove oil from water using semi-permeable barriers. The focus of this review is on polymeric membranes derived from polymer blends, which show improved mechanical strength, thermal stability, and resistance to fouling. Additionally, the role of nanomaterials such as titanium dioxide, graphene oxide, and iron nanoparticles is discussed for their ability to boost membrane porosity, permeability, and oil separation efficiency. Recent research also looks into incorporating green nanoparticles made from agricultural waste, including banana and eggplant peels. These bio-based additives provide sustainable, low-cost, and eco-friendly alternatives that enhance membrane hydrophilicity, antifouling properties, and overall separation performance. Finally, this review highlights existing challenges and emphasizes the need for further research to scale up these membrane technologies for industrial oily wastewater treatment, focusing on long-term stability, economic viability, and environmental safety.