Green nanotechnology integrates the principles of sustainability with precision of nano science. It offers environment friendly solutions across multiple sectors. These sectors include healthcare, agriculture, energy and environmental remediation. This approach prioritizes low toxicity, energy efficiency, and biodegradable nanomaterials. So, it emphasizes biological and biotechnological perspectives. For this purpose, nanomaterials are synthesized through plant extracts, microbial systems, enzymes, and renewable bioresources. These biosynthetic methods align closely with goals of circular economy and sustainable development. These enable applications ranging from nano-based wastewater treatment to biocompatible drug delivery systems. Despite its growing relevance, green nanotechnology faces various challenges. These include variability in bio-based synthesis, limited scalability, regulatory problems, and knowledge gaps across interconnected disciplines. Advanced tools from biotechnology are emerging to enhance reproducibility, pathway prediction, and material customization. Recent developments demonstrate its increasing industrial adoption and international support. But broader implementation requires coordinated research, policy innovation, and interdisciplinary collaboration. Green nanotechnology stands at a critical juncture. It can contribute to safe material design, sustainable innovation, and long-term ecological and human health outcomes.