This book provides a comprehensive exploration of green nanotechnology, covering principles, applications, and ethical considerations. The book begins with an introductory exploration of nanotechnology, followed by in-depth discussions on the synthesis of ozone-friendly nanomaterials and the emerging practice of green synthesis. It delves into the diverse applications of green nanoparticles, spanning biomedical applications, tissue engineering, biosensors, antimicrobials, and vaccine development. It explores applications of nanotechnology in environmental sciences including, bioremediation, microengineered ceramics for environmental protection, and the modification of advanced nano-polymer composites. The environmental fate and ecotoxicological implications of nanomaterials are thoroughly examined, followed by discussions on the energy-saving potential and sustainable fuel development in the realm of green nanotechnology. The book concludes with a focus on responsible and ethical considerations, addressing the legal, socio-economic, and ethical impacts of nanotechnology, making it an important resource for researchers, academics, and professionals in nanobiotechnology and biomedical sciences.