Oil production entails the generation of large volumes of complex effluents that contain emulsified oil in water. Difficult to manage, the use of membrane separation processes (MSP) is an interesting option for the treatment of oily effluents, separating oil-in-water (o/w) emulsions with high efficiency. Modifying the surface of membranes with metals minimizes fouling, which is the main drawback of MSP. Through a survey of scientific papers and patent applications, this review demonstrates the technological development of membranes containing metals or metallic nanoparticles (MNP) for separating o/w emulsions. In total, 314 articles and 339 patent filings were retrieved by July 2023. The beginning of growth in the number of documents retrieved was more significant in 2018 for articles and in 2017 for patents. Asia was the largest highlight, with emphasis on China, which had 76.97% of the production of articles and 98.31% of patent applications on the continent, justified by investment in Research and Development (R&D). Metals, such as Fe, Zn, Cu, and Ti have been used to modify membranes and substrates. Polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), and polypropylene (PP) membranes and carbon-based primary substrates were used for their preparation. Advancements in membranes containing metals or MNP for the separation of o/w emulsions can have a positive impact on Sustainable Development Goals (SDG). This developing field anticipates increased involvement in nanotechnology, the development of systems that enable both the separation and oxidation of organic compounds, and a variety of methods or combinations of approaches to synthesize increasingly efficient membranes.