Water pollution caused by dyes and micropollutants from industrial and agricultural activities poses significant environmental and health risks. Conventional water treatment methods often prove inadequate in addressing these contaminants due to their persistent and complex nature. In recent years, biogenic nanocomposites have emerged as a promising solution for wastewater remediation. These materials, synthesized from naturally occurring precursors, offer eco-friendly, cost-effective, and sustainable alternatives to synthetic adsorbents and catalysts. This review highlights the potential of biogenic nanocomposites for the efficient removal of dyes and micropollutants from wastewater. The unique properties of these nanocomposites, including large surface area, high reactivity, and tunable surface functionalities, make them ideal for adsorption, photocatalysis, and degradation of hazardous contaminants. Various biogenic sources, such as agricultural waste, microorganisms, and plant extracts, are explored in the synthesis of these materials. We also discuss the mechanisms of dye and pollutant removal, along with the challenges and future perspectives for large-scale applications. The integration of biogenic nanocomposites into wastewater treatment technologies holds great potential for achieving cleaner water and promoting environmental sustainability.