The United Nations has introduced 17 Sustainable Development Goals for the well-being of human beings. The sixth goal discusses the importance of clean water and sanitation. While the availability of clean water is one of the essential factors for sustaining human life, the hard reality is that the pollution rate of water bodies is on the rise. This chapter delves into the fascinating realm of sustainable and environmentally friendly water purification techniques using advanced nanomaterials, which are derived from green sources. The importance of green technology in the synthesis of nanomaterials and the utilization of green nanostructured materials in photocatalytic water purification are the main thrusts of this chapter. The various types of nanomaterials obtained through green synthesis and the different types of pollutants that should be eradicated during water purification are also discussed in this chapter. The photocatalytic mechanism followed by these green nanostructured photocatalysts will be explained in detail. The measures in improving the photocatalytic efficiency of green nanostructured materials are another discussion point that can attract the interest of scientists working in this field. Finally, this chapter also elucidates the challenges and future prospects of green nanostructured photocatalysts in the purification process of water bodies.