Gamma-aminobutyric acid (GABA) modulates photosynthesis and maintains a delicate balance between carbon and nitrogen metabolism under both optimal and stress conditions. As a non-proteinogenic amino acid, GABA is actively involved in redox homeostasis and signalling pathways that regulate photosynthetic efficiency. GABA metabolism interplays with key photosynthetic processes, including CO2 assimilation, ETC dynamics, and ATP synthesis. Thus, understanding the mechanistic basis of GABA function in photosynthetic protection provides insights into improving plant resilience and productivity through metabolic engineering and agronomic interventions.