Textile wastewater is a significant environmental problem because it has high content of heavy dyes and metals, which can be harmful to the environment and humans. Conventional treatments are not always successful in eliminating these difficult-to-degrade pollutants, and hence new technologies like nanotechnology are required. This chapter reflects on how nanoparticles can be used as an effective alternative. It shows how they can address the problems of traditional techniques and help with the increasing issue of pollution due to textile wastewater. It focuses on three nanoparticle’s types that are very important in the wastewater treatment process. These are metal oxide nanoparticles, carbon-based nanomaterials, and zero-valent metal nanoparticles. Metal oxide nanoparticles are photocatalytically active nanoparticles because they can degrade dye when exposed to light. Carbon-based nanomaterials are highly adsorbent. However, zero-valent metal nanoparticles will do both processes, which are adsorption and chemical reactions, to render contaminants harmless, using both processes. All these technologies have great potential. However, some limitations that will have to be overcome include possible toxicities of nanoparticles, aggregation of nanoparticles, and high production costs.