<p> <!--Query ID="Q1" Text="Please check and confirm if the authors and their respective affiliations have been correctly identified. Amend if necessary." Resolved="yes"-->This study aimed to determine the effects of selected plant growth-promoting silver nanoparticles (AgNPs) on certain physiological traits, plant growth, enzyme activity, and plant nutrient content of lettuce grown under different irrigation regimes. In this research, four irrigation regimes were tested as experiments in a randomized complete block design layout: I₁₀₀ (full irrigation), I₈₀ (20% deficit), I₆₀ (40% deficit), and I₄₀ (60% deficit). Additionally, four nanoparticle doses (AgNP₀, 0 ppm; AgNP₂₀, 20 ppm; AgNP₄₀, 40 ppm; and AgNP₈₀, 80 ppm) were applied to the crop. The results demonstrated that the head diameter of lettuce decreased by 28% and 30% under the I₆₀ and I₄₀ water stress conditions, respectively. However, AgNPs enhanced the head diameter of lettuce by 10.9% compared to the control (non-application of AgNPs). The application of AgNPs increased the nutrient content of lettuce, including potassium (K), sodium (Na), iron (Fe), copper (Cu), and manganese (Mn), by 38%, 19%, 23%, 367%, and 20%, respectively. Plant height was 98.2% higher in the full irrigation treatment (I₁₀₀) than in the 40% irrigation treatment (I₄₀). Dry matter content was 10.2% higher in the AgNP₈₀ treatment compared to the AgNP₀ treatment. In addition, the highest catalase (CAT) enzyme content was obtained in the AgNP₄₀ treatment. The present research suggests that applying AgNPs represents a sustainable and eco-friendly strategy for improving lettuce’s plant growth and nutrient uptake under water stress conditions. Therefore, AgNPs can be used in drought stress tolerance studies.</p>