Heavy metal contamination in wastewater has become a pressing global issue, posing serious risks to environmental and public health. Traditional remediation technologies, while effective to an extent, often suffer from limitations such as high cost, low selectivity, and secondary pollution. In recent years, the development and application of eco-friendly nanomaterials have emerged as promising alternatives due to their high surface area, unique physicochemical properties, and sustainable synthesis pathways. This review explores the synthesis, characterization, and practical application of green nanomaterials for the remediation of heavy metals in wastewater. It evaluates current advancements, discusses mechanisms of metal removal, and identifies the challenges and future directions in this rapidly evolving field.