An update on the current research and development of wetland treatment technologies for wastewater treatment is provided in this paper. This article focuses on wetland applications in wastewater treatment (as an advanced treatment unit or a decentralized system), and nutrient and pollutant removal (metals, industrial and emerging pollutants including pharmaceutical compounds). A summary of studies involving the effects of vegetation, wetland design and operation, modeling, hybrid and innovative systems, landfill leachate treatment, and pathogen removal is also included.