<p>Crude oil contaminants, including water/oil emulsions, asphaltene depositions, and the leakage of polycyclic aromatic hydrocarbons (PAHs) into soil and water, pose substantial threats to ecosystems and refining processes. To tackle these issues, this study reviews recent advancements in the application of ultrasonic waves (UWs) to mitigate these pollutants. Notably, ultrasound demonstrates significant potential to accelerate emulsion separation, substantially reduce the viscosity of heavy crude oils, and markedly enhance the permeability of reservoirs and contaminated soils, with performance varying based on specific experimental conditions such as frequency, power, and crude oil type. Consequently, this technology has advanced environmental remediation by decomposing asphaltene aggregates and removing PAHs from complex soil pores. Furthermore, the thermal effects and microjet formation associated with cavitation were confirmed by computational fluid dynamics (CFD) and molecular dynamics (MD) simulations. Although ultrasound reduces reliance on toxic chemicals compared to conventional methods such as acidizing and surfactant injection, its net environmental advantage is not unconditional; it materializes only when the reduction in chemical consumption outweighs the electrical energy demand of sonication, a condition most reliably satisfied in high-asphaltene, chemically intensive treatment scenarios. However, there are still several challenges, such as scalability of processes, which make this technique limited in its industrial applications. Future research will be directed at developing energy-intensive apparatus, integrating ultrasound with biocompatible nanoparticles, and applying artificial intelligence (AI) and machine learning (ML) for process optimization. Overall, this review offers a road map for future studies on petroleum refining and environmental restoration.</p>