<p>Evapotranspiration (ET) is a crucial component of the water cycle, significantly impacting climate regulation, hydrological processes, agriculture, and water resource management. This review offers a comprehensive analysis of ET trends across various climatic zones in India, examining regional variations, measurement methodologies, and underlying causes. The study highlights seasonal and spatial fluctuations in ET, with some regions experiencing declining ET due to reduced solar radiation and land-use changes, while others show increasing trends driven by temperature rise and agricultural expansion. Factors such as monsoon variability, deforestation, irrigation practices, and urbanization have a significant influence on ET patterns across the country. Different measurement techniques, including the Penman-Monteith equation, remote sensing, and statistical trend analysis, are examined for their effectiveness in estimating ET. The study also discusses the implications of ET changes for water resource management, agricultural productivity, ecosystem health, and climate modelling. Given the complex interactions between ET, climate change, and land-use dynamics, the review underscores the need for advanced monitoring techniques, AI-driven modelling approaches, and region-specific adaptation strategies to ensure sustainable water resource management. Future research should focus on enhancing the accuracy of ET estimation, understanding the interactions between climate and ET, and developing predictive models for improved environmental and agricultural planning in India.</p>