Nanomaterials play a significant role in various fields due to their versatile surface functional properties and diversified applications. Nano catalysts are the main constituents of nano catalysis with dimensions less than 100 nm, and they exist in the form of metal oxides or inorganic materials like semiconductors. The improved selectivity and efficiency of nano catalysts find potential application in resolving various complex industrial issues by offering sustainable solutions. Nano photo catalysts are receiving significant attention due to their extraordinary physical properties, high thermal and chemical stability, low environmental impact, strong oxidation capability, and bountiful potential applications in solar energy systems. Nano photo catalysts are an excellent support material for pollution-control applications. This chapter deals with the various methods of synthesis of nano photocatalysts and their application in wastewater treatment. The advantages and limitations of the nano photocatalysts are presented in this chapter.