The green synthesis of metal oxide nanoparticles has emerged as a sustainable alternative to conventional chemical and physical synthesis methods because it reduces the use of toxic reagents, minimizes waste generation, and utilizes renewable biological resources. Copper(I) oxide (Cu₂O) nanoparticles have attracted considerable interest owing to their distinctive optical, catalytic, and antimicrobial properties. The present study focuses on the environmentally benign synthesis of Cu₂O nanoparticles using plant- and agricultural-waste-derived extracts as natural reducing and capping agents. Waste materials, including *Daucus carota* peel, *Artocarpus heterophyllus* seed, and *Cocos nucifera* husk, were selected as potential bioresources for nanoparticle synthesis. The phytochemicals present in these materials, including phenolics, flavonoids, alkaloids, tannins, saponins, and other bioactive compounds, facilitate the reduction of Cu²⁺ ions and contribute to the stabilization of the synthesized nanoparticles. The proposed approach provides an economical and environmentally compatible route for producing Cu₂O nanoparticles while simultaneously promoting the valorization of agricultural waste. The synthesized nanoparticles can be investigated for their physicochemical characteristics and antimicrobial performance against representative Gram-positive and Gram-negative bacterial strains. Their antibacterial activity is associated with interactions between nanoparticles and bacterial cell envelopes, potentially resulting in membrane disruption, oxidative stress, and inhibition of essential cellular processes. The study highlights the potential of waste-derived Cu₂O nanoparticles as sustainable antimicrobial materials for applications in biomedical, environmental, and healthcare-related fields. Overall, the proposed green synthesis strategy combines waste utilization, nanotechnology, and antimicrobial research to develop potentially effective and environmentally responsible nanomaterials.