Nanotechnology is becoming an indispensable component of the Sustainable Development Goals (SDGs), particularly in the areas of environmental preservation and circular economy. Several anthropogenic activity-induced issues, like pollution, biodiversity loss, climate change, etc., have posed challenges in achieving these goals by 2030. Nanotechnology holds significant implications for global sustainability endeavors as evident from its presence in numerous scientific domains, including engineering, medicinal science, energy, and the environment. Green nanotechnology offers an interesting avenue for the synthesis of safe and cost-effective nano-materials/particles with requisite specification. Green synthesis of nanomaterials (NMs) employs bio-resources such as bacteria, fungi, herbs, and agricultural residues, which lowers the synthesis process’ carbon footprint. This chapter discusses the green nanotechnology-enabled solutions for wastewater treatment under the ambit of SDG-goal 6 “clean water and sanitation.” We also talk about potential green NMs, their characteristics and mechanisms for wastewater management applications, benefits and drawbacks in comparison with current methods, and the challenges and future scope of research activities.