The heavy input of emerging contaminants into the environment and natural wetlands has paved the way for constructed wetlands. A constructed wetland is an artificial marsh or swamp that has been designed and constructed to utilize the natural processes involving wetland vegetation, soils, and their associated microbial assemblages to assist in emerging contaminant and metal phytoremediation. Constructed wetlands are a natural alternative to technical methods of wastewater treatment. In this chapter, we briefly discuss the importance of wetland plants and their role in the phytoremediation process, particularly for diverse emerging contaminants. In constructed wetlands, there may exist several mechanisms of phytoremediation. Also, diverse types of constructed wetlands are discussed. Further, plant microbe interaction and the role of rhizospheric organisms are discussed. Moreover, the impact of environmental factors on the performance of the constructed wetland treatment system should also be taken into consideration. The role of the hydraulic loading rate (HLR) and hydraulic retention time (HRT) and the prospective features of the constructed wetland treatment system are also covered in this chapter. Further, several global case studies (from both tropical and temperate countries) on constructed wetlands and associated phytoremediation are discussed. These wetlands have proved to be efficient, cost-effective, and environmentally friendly.