Cleaning a contaminated site and making it habitable is a challenge which is of universal interest due to persistence of different kinds of pollutants at major sites and landfills. Contaminant types range from organic such as pesticides, dyes and drugs to inorganic including nuclear pollutants and heavy metals depending upon the type of site. Variation in the types of pollutant demands understanding of remediation processes as well as exploration of new materials. Traditional remediation techniques often come with drawbacks such as high costs, low efficiency, and possible damage to surrounding environments. In recent years, nanotechnology has emerged as a promising way for addressing these challenges. Nanomaterials with their unique properties and high surface area-to-volume ratios, offer solutions for the efficient removal and remediation of contaminants from soil, water, and air. This chapter provides an overview of the applications of nanomaterials in the remediation of contaminated sites. Several nanomaterials are included with their preparation methods, and mechanisms of contaminant removal. The chapter also discusses the factors influencing the efficiency of nanomaterial-based remediation strategies, including environmental conditions, material stability, and possible risks related to their use. Case studies highlighting successful applications of nanomaterials in different contaminated sites are also presented. Finally, the chapter concludes with a discussion on the prospects and challenges in the area, putting emphasis on the need for further research for sustainable remediation practices.