Abstract <p>The enormous increase in population and urban development spurred industrial progress all across the world, especially in the textile industries. The textile sector which is direct contributor to GDP growth of third world countries run by consuming huge number of dyes along with surplus water, from which more than 10% of dyes poured into nearby water bodies which are harmful for living creatures. Among all available routes for wastewater treatment, photocatalytic degradation of dyes using heterogeneous photocatalyst (AOP) has an edge due to low cost, non-toxicity, simple separation, reusability, and stability. Recently, biosynthesized CuO nanoparticles are becoming immensely popular due to its versatile applications, among which wastewater remediation considered as most suitable. In green synthesis of CuO, only plant mediated biosynthesis was considered due to the limitations of other green methods of synthesis. This review covers biosynthesis of CuO from different plant parts, mechanism of biosynthesis and effect of different parameters on biosynthesis. The review explores CuO nanoparticle photocatalytic application against different dyes, finding optimized degradation condition, mechanistic route for degradation and cost analysis for industrial large-scale production. The outcome of this study could facilitate significant development for academic as well as industrial community engaged in water remediation.</p>