Water is a major resource in our day to day life. It is recognized as one of the major source of evolution from origin to degree of civilization. But now a day’s waste water is becoming a major hazard in present scenario and waste water treatment is evolving as a major area of investigation. Nanoparticles are having a great prospective to be used in waste water treatment. Its matchless characteristic of having high surface area can be used efficiently for removing toxic metal ions, disease causing microbes, organic and inorganic solutes from water. Various classes of Nanoparticles are proved to be efficient for water treatment like metal-containing nanoparticles (like metal-oxides, metal-sulphides), carbonaceous Nanoparticles and zeolites. Nanotechnology has led to numerous well-organized ways for treatment of waste water in a more accurate way on both small as well as large scale. This paper presents a review on the role of Nanotechnology for waste water treatment.