<p>The treatment of oily wastewater continues to pose a critical global challenge due to the complex and variable composition of oily wastewater and the inherent limitations of conventional technologies. Coagulation/flocculation, although mature and cost-effective, requires continuous innovation. This review uniquely establishes a bridge between molecular-level mechanistic insights and practical, large-scale engineering practices, offering a systematic and critical analysis of recent advancements in coagulation/flocculation for oily wastewater treatment, with a particular focus on material innovations and integrated technologies. We highlight that precise molecular customization of flocculants, especially through hydrophobic modification and tailored charge distribution, significantly enhances oil removal efficiency and selectivity, outperforming traditional counterparts. Furthermore, the synergistic integration of coagulation/flocculation with advanced oxidation processes (AOPs, e.g., ozonation) has been demonstrated to be highly effective and economical for degrading recalcitrant organic compounds and improving floc formation. A critical analysis reveals that optimal flocculant selection and dosage are highly context-dependent, largely influenced by the wastewater matrix and oil characteristics, thus necessitating standardized and transparent reporting in future research. Beyond pollutant removal, this review emphasizes the economic and environmental advantages of oil resource recovery, identifying it as a crucial component of sustainable wastewater management. Ultimately, we outline key challenges, including process scalability, sustainable sludge management, and the development of biodegradable flocculants, thereby providing actionable guidelines for the design of next-generation treatment systems tailored to the characteristics of specific oil pollutants.</p>