<p>Groundnut (<i>Arachis hypogaea</i>), a major global oilseed crop, often suffers large yield losses when drought coincides with the reproductive stage. This study evaluated the foliar application of red seaweed (<i>Gracilaria tenuistipitata</i> var. <i>liui</i>) extract as a nature-based biostimulant to enhance drought resilience of the variety BARI Chinabadam-8 using agronomic, physiological, and remote-sensing approaches. Four treatments were applied: I (irrigation), D4 (drought + 4% w/v seaweed extract), D10 (drought + 10% w/v seaweed extract), and D0 (drought without seaweed extract). Drought-stressed plants treated with both concentrations (D4 and D10) of seaweed extract exhibited agronomic traits (biomass, plant height, and fresh yield) statistically similar to the irrigated control (I). For physiological responses (stomatal conductance, leaf vapor pressure deficit, and transpiration rate), 10% seaweed-treated plots exhibited no significant differences compared to the irrigated control (I). Unmanned aerial vehicle (UAV)-based thermal imaging indicated canopy cooling of 0.44–0.50&#xa0;°C in seaweed-treated plots relative to the drought control. Compared to the irrigated control (I), D0 exhibited a 48.84% yield reduction, whereas D4 and D10 mitigated this loss to 25.64% and 37.04%, respectively. Vegetation indices, including the green difference vegetation index (GDVI), normalized difference vegetation index (NDVI), soil-adjusted vegetation index (SAVI), and wide dynamic range vegetation index (WDRVI), were strongly correlated with physiological traits and yield. A predictive model combining physiological and remote sensing data accurately estimated dry yield (R² = 0.92, RMSE = 0.25 t ha⁻¹). These findings support red seaweed extract as a promising nature-based approach to enhance reproductive-stage drought resilience in groundnut.</p> Graphical Abstract <p></p>