<p>Drought stress is a major abiotic stress that jeopardises global crop production. In recent years, <i>Avena sativa</i> has gained popularity as a nutritious food due to its health benefits. This study tested the hypothesis that exogenous salicylic acid alleviates drought stress by suppressing endogenous ROS signalling and enhancing the antioxidant defence system in <i>Avena sativa</i>. Fifteen-day-old seedlings were exposed to various treatments, including well-watered and water-deficient conditions, with and without foliar application of SA. Plant samples were collected after 65 days of sowing and analysed for morpho-physiological and biochemical responses. Results showed that drought stress has an adverse effect on photosynthetic pigments, sugars, proteins and overall growth. At the same time, proline, hydrogen peroxide (H₂O₂), superoxide radical and malondialdehyde (MDA) content were enhanced in plants; however, foliar application of 1mM salicylic acid enhanced chlorophyll, carotenoids, proline, sugars and proteins. A significant enhancement was observed in the plant defence system, attributed to increased activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR) induced by exogenous salicylic acid treatment under drought stress. These findings support the hypothesis that exogenous application of SA manages oxidative stress and other metabolic processes in <i>Avena sativa</i>.</p>