Oil leakage and organic solvent industrial accidents harm the ecosystem, especially aquatic and marine life. Oil–water separation is required to combat this issue, which substantially enhances the ecosystem and recovery of oils from water bodies. In this aspect, significant efforts have been made by scientists to develop newer composite materials that efficiently separate oils from water bodies with exceptional recyclability. Membrane filtration is an efficient option for oil–water separation due to its ability to separate oil from water without involving any chemicals. However, relatively less water permeability and a high degree of surface fouling limit their applicability. The advent of two-dimensional nanomaterials (2D-NMs) gives newer insight in developing membranes due to their exceptional characteristics like hydrophobicity/hydrophilicity, selectivity, antifouling ability, flexibility, and stability. Incorporating 2D-NMs within the polymeric membranes makes them exceptional candidates for removing oil from water. Moreover, 2D-NMs offer rapid sorption/desorption rates and boost water transportation. Additionally, 2D-NMs provide roughness that significantly enhances the fouling resistance in the polymeric membrane. This review focuses on properties of 2D-NM-based polymeric membrane and their roles in oil–water separation. We also discussed strategies to improve the oil–water separation efficiency. Finally, we discussed oil–water separation’s outlook and prospects using 2D-NM-based polymeric membranes. This review might provide new insight to the researchers who work on oil–water separation.