Legumes, especially peas, are sensitive to water shortages, which are becoming increasingly common because of climate change. Peas are beneficial for soil and crop rotation and as a source of protein in nutrition. Therefore, discovering new agrotechnical tools and maintaining plant resistance to environmental influences is essential. The aim of this study was to investigate the effects of silica nanoparticles (SiO₂ NPs) on drought-stressed peas (Pisum sativum L., ‘Respect’) via different exposure routes: through foliar spraying and root watering. The research was conducted in a greenhouse. Ten green pea seeds (‘Respect’) were sown in 10 L vegetative pots and were thinned up to 7 plants per pot after germination. When the peas reached the 39 BBCH growth stage (had nine or more visibly extended internodes), they were foliar sprayed to full wetness (ca. 14±0.5 mL plant⁻¹) or watered (100±1 mL per pot) with suspensions containing 12.5, 25, and 50 ppm of SiO₂ NPs. Untreated NPs plants were watered or sprayed with distilled water. During the 10-day drought period, low substrate moisture (30%) was maintained for peas exposed to SiO₂ NPs, and other plants (controls) were grown under regular substrate moisture (80%). At the end of the experiment, peas were harvested to assess the impact of SiO₂ NPs and drought on plant growth indicators and enzymatic (SOD, GR, APX) and non-enzymatic (TPC, FRAP) antioxidants activity. The results showed that treatment at a concentration of 50 ppm SiO₂ NPs strongly affected pea leaf area, shoot height, and fresh biomass when plants were grown in drought conditions. In addition, positive effects on the activity of enzymatic (APX, CAT, GR, SOD) and non-enzymatic (TPC, DPPH, ABTS, FRAP) antioxidants in the pea plant were found. The SiO₂ NPs reduced hydrogen peroxide and lipid peroxidation in drought-affected plant tissue. SiO₂ NPs protected green peas from the adverse effects of drought stress and maintained pea yield.