As the global demand for sustainable energy storage grows, the search for efficient anode materials for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) has become of scientific interest. This study theoretically investigates the potential of green phosphorene, a two-dimensional (2D) material, as an anode material for alkali metal-ion batteries. Using density functional theory (DFT) calculations, we investigated the adsorption behavior of lithium and sodium ions on green phosphorene, evaluating structural stability, electronic properties, and ion diffusion pathways. Our results show that green phosphorene exhibits favorable adsorption energies for both Li and Na ions, while maintaining excellent structural integrity across various ion concentrations. Additional, a semiconductor-to-metal transition was observed during the lithiation and sodiation processes, further supporting its viability as a high-performance anode material. The calculated specific capacities and open-circuit voltage (OCV) profiles for green phosphorene are competitive with or superior to, conventional materials. Lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), contributing to advancements in more sustainable and efficient energy storage technologies. © 2025 American Chemical Society.