In recent years, the demand for sustainable and nutritious plant-based protein sources has surged, driven by environmental impact, animal welfare, and personal health concerns. Green leaf proteins have garnered significant attention among the array of plant-based proteins due to their sustainability, nutritional richness, and versatility. This review explores the diverse landscape of green leaf proteins, focusing on their sources, nutritional profiles, sustainability attributes, technological applications, and potential contributions to global food security. Drawing upon scientific literature and empirical evidence, this review elucidates the pivotal role that green leaf proteins play in fostering sustainable food systems and mitigating the challenges posed by conventional protein sources. The challenges and opportunities associated with harnessing green leaf proteins for commercial-scale production are discussed, alongside considerations for policymakers, researchers, and industry stakeholders.