Technology advancement improves the quality of life, however, it might also introduce new pollutants to the ecosystem, which needs to deal with for the goal of a sustainable ecosystem. Municipal and industrial wastewater has always been important in improving the quality of life while maintaining the sustainability of our planet simultaneously. The diversity of pollutants in wastewater requires more advanced and demanding treatment processes. The ozonation, as a crucial part of the advanced oxidation processes, is a superior oxidation method compared to traditional oxidation methods. After the recognition of ozone as GRAS (generally recognized as safe), its applications have diversified and is used currently for microbial inactivation, degradation of recalcitrant organic compounds, removal of a diverse range of micropollutants, solubilization and reduction of sludge, and removal of color and odor components in wastewaters treatment processes. However, some considerable challenges still exist towards its universal application, such as high ozone generation costs, diversity of pollutants, and formation of ozonation by-products, which still require further studies. The main theme of this review paper is the transformation of traditional oxidation methods into advanced oxidation processes and the role of ozonation in this regard, including its applications, by-products, and its comparison with the traditional oxidation methods and advanced oxidation processes.