GABA plays a multifaceted role in modulating defense mechanisms, particularly under oxidative stress. As plants encounter environmental stressors, such as drought, salinity, and heavy metals, oxidative stress is often induced, characterized by the accumulation of Reactive oxygen species (ROS). GABA modulates metabolic pathways linked to stress resilience that influence antioxidant systems via the synthesis of antioxidant enzymes, balance ROS levels, and maintain cellular redox homeostasis. GABA signaling also intersects with other metabolic and hormonal pathways to ameliorate tolerance to oxidative stress, boosting the overall defense capacity. Emphasis is placed on recent advances in understanding GABA’s involvement in ROS scavenging, signaling pathways, and its regulatory impact on plant growth and survival under adverse conditions.