<p>Water pollution is a global challenge caused by industrial discharge, agricultural runoff, and insufficient wastewater treatment. Conventional treatment is widespread but faces challenges such as low removal efficiency, high costs, and secondary pollution. Sustainable, cost-effective adsorbents derived from agricultural byproducts, biomass, and minerals are promising alternatives but often exhibit low adsorption capacity, poor selectivity, and limited regeneration. Nanotechnology has improved these materials by increasing surface area, adding functional sites, and enhancing mass transfer. Reported nano-engineered biosorbents demonstrate adsorption capacities approaching 80–100&#xa0;mg/g for several dyes, with removal efficiencies frequently exceeding 90–99% depending on the adsorbent type and operating conditions. This review analyzes the integration of nanotechnology with natural adsorbents for the remediation of water pollutants. A comprehensive literature survey was conducted using major scientific databases. These include Scopus, Web of Science, PubMed, and Google Scholar. The survey covers publications from 2010 to 2025. The review critically evaluates major classes of nano-engineered natural sorbents, including nano-biochar, carbon-based nanomaterials, metal and metal oxide-nanoparticle-loaded biomass, magnetic nanocomposites, and polymer–biomass nanohybrids. Unlike previous reviews, which focus primarily on either natural adsorbents or engineered nanomaterials separately, this review provides an integrative and critical assessment of nanotechnology-enabled natural sorbents, emphasizing their synergistic advantages for sustainable water purification.</p>