In recent years, the field of green synthesis for carbon dots has seen significant advancements in the development of materials for heavy metal ion sensing applications. A variety of eco-friendly and sustainable approaches have been explored to synthesize carbon dots (CDs) with enhanced sensing properties. These materials have shown great promise in detecting heavy metal ions due to their high sensitivity, selectivity, and low detection limits One of the key advancements in this area is the utilization of natural sources such as biomass, organic waste, and plant extracts as precursors for the synthesis of CDs. These green precursors not only contribute to the sustainable nature of the synthesis process but also result in the production of carbon dots with unique surface chemistry and optical properties. In addition to the synthesis and functionalization strategies, the understanding of the underlying mechanisms governing the interaction between CDs and heavy metal ions has advanced significantly. This improved understanding has facilitated the design of CDs with tailored sensing capabilities and improved overall performance. Overall, the recent progress in the green synthesis of CDs for heavy metal ion sensing holds great promise for the development of cost-effective, environmentally friendly, and high-performance sensing platforms with potential applications in environmental monitoring, industrial safety, and healthcare diagnostics.