Microwave (MW) irradiation has gained a great deal of attention owing to the molecular level heating. However, the commercialization of MW technology for real-time wastewater (WW) treatment requires the understanding of basic mechanism of MW and MW coupled treatment methods. This review addresses the basic theory and mechanism of MW, current application of MW in WW treatment, MW reactors and economical aspects of MW in WW treatment. The different combinations of MW application in WW treatment, including MW alone, MW with oxidants, MW with catalyst and MW with advanced oxidation processes (AOPs) are discussed in detail. Moreover, the effect of MW heating and the factors affecting MW coupled treatment methods are discussed with respect to the treatment efficiency. Finally, the future research challenges in the application of MW for WW treatment are emphasized.