This review discusses recent progress in defect-engineered metal oxides for photocatalytic environmental remediation. Metal oxides, such as binary oxides, perovskites, and spinels, are promising candidates for photocatalytic applications due to their excellent physicochemical properties. Defects, such as oxygen vacancies and doping, play a crucial role in enhancing the photocatalytic activity of these materials by altering their electronic structure, increasing light absorption, and reducing electron-hole recombination. Various strategies have been employed to introduce defects, including annealing under different atmospheres, chemical reduction, and heterojunction formation. These defects can significantly improve the efficiency of photocatalytic processes, making metal oxides a viable solution for environmental remediation. The review summarizes the current research, challenges, and potential solutions in this field, highlighting the importance of defect engineering in enhancing the performance of photocatalytic materials.This review discusses recent progress in defect-engineered metal oxides for photocatalytic environmental remediation. Metal oxides, such as binary oxides, perovskites, and spinels, are promising candidates for photocatalytic applications due to their excellent physicochemical properties. Defects, such as oxygen vacancies and doping, play a crucial role in enhancing the photocatalytic activity of these materials by altering their electronic structure, increasing light absorption, and reducing electron-hole recombination. Various strategies have been employed to introduce defects, including annealing under different atmospheres, chemical reduction, and heterojunction formation. These defects can significantly improve the efficiency of photocatalytic processes, making metal oxides a viable solution for environmental remediation. The review summarizes the current research, challenges, and potential solutions in this field, highlighting the importance of defect engineering in enhancing the performance of photocatalytic materials.