The increasing discharge of untreated or inadequately treated wastewater poses a serious threat to public health and aquatic ecosystems, particularly in regions lacking centralized treatment infrastructure. As a nature-based and cost-effective alternative, constructed wetlands (CWs) have gained global recognition for their ability to treat a wide range of wastewater types including municipal sewage, industrial effluents, agricultural runoff, and landfill leachate through integrated physical, chemical, and biological processes. CWs replicate the purifying functions of natural wetlands and are particularly valued for their adaptability, low energy inputs, and capacity to remove both conventional pollutants and emerging contaminants. To inform future research and policy development, this chapter presents a comprehensive bibliometric and content-based analysis of 5,388 peer-reviewed publications from 2000 to 2025 using data from the Scopus database and tools such as VOSviewer and the Bibliometrix R package. The analysis reveals a strong upward trend in publication output (annual growth rate: 16.9%), with China, the USA, and India emerging as leading contributors. Keyword co-occurrence analysis identified six dominant thematic clusters including nitrogen removal, phytoremediation, emerging contaminants, and microbial interactions. Notably, hybrid CWs demonstrated up to 25-fold higher nitrogen removal efficiency in human-associated environments compared to non-human systems. Future research is expected to focus on (1) optimizing design and substrate configuration for pollutant-specific removal, (2) advancing real-time monitoring and smart automation, and (3) evaluating the long-term sustainability and cost-effectiveness of CWs. This bibliometric overview contributes a robust synthesis of current research trends, knowledge gaps, and future directions, supporting the advancement of resilient, scalable, and eco-engineered wastewater treatment solutions.