Advanced oxidation processes (AOPs) have attracted considerable attention in recent years for the treatment of petroleum refinery wastewater, mainly because of their ability to degrade persistent organic pollutants. Despite this, their practical application at an industrial scale remains limited. This review discusses the main factors that restrict the performance of AOPs in real wastewater systems. Particular emphasis is placed on the effects of wastewater composition, including radical scavenging, variability of the matrix, and the presence of complex organic and inorganic constituents. In addition, issues such as incomplete mineralization and the formation of potentially toxic by-products are highlighted. Operational challenges, including high energy and chemical consumption, pH sensitivity, and catalyst- related limitations, are also addressed. While combining AOPs with other treatment methods can improve overall efficiency, such approaches often increase process complexity and cost. Overall, further research is needed to better understand process behaviour under real conditions and to support the development of more practical and scalable treatment strategies.