Stresses are the most important factor reducing crop production worldwide.Various techniques such as genetic modification for the production of resistant cultivars, improved plant nutrition and pretreatment with some compounds have been proposed to increase tstability of the production system and reduce the consumption of agricultural chemicals. Currently, according to the great interest for natural antioxidants, bioactive antioxidant peptides, extracted from plant proteins, have been studied. Olive-derived proteins are important source for bioactive peptides and protein hydrolysates.In this study, the proteins of industrial olive oil by-products including leaf, pomace and seed was examined using the standard Bradford assay and the extracted proteins were characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE).Olive PHs were prepared using commercial enzyme, Alcalase and the antioxidant activity of them were measured by three antioxidant assays.In DPPH radical scavenging assay, inhibition percentage of seed, pomace and leaf PH were found to be 58.7, 52.3 and 20%, respectively.The hydroxyl radical scavenging of seed, pomace and leaf PH showed 47.6, 43.6 and 26.1% of inhibition.The seeds were the samples yielding the PH with the highest lipid peroxidation inhibition capacity (87.8%).Among all hydrolysates, seed PH showed highest antioxidant activity as compared to other hydrolysates and selected for second experiment.In order to investigate the effect of pH o drought alleviation, an experiment was set up as factorial in completely randomized design with two factors, including seed PH application at three levels (0, foliar application at 0.15% or soil drenching at 0.15%) and drought stress at two levels (full irrigation at FC level or 50% FC) and five replications. The results showed that drought stress decreased chlorophyll index and chlorophyll fluorescence, while the levels of them in PH treated plants did not show a significant difference compared to control plants.Plant treatment with 0.15% PH decreased ionic leakage and plants showed higher proline and soluble carbohydrate concentrations as well as better relative water content than non-treated plants.The obtained results showed that the olive seed PH can be effectively utilized for reducing damages caused by drought stress. Keywords: Antioxidants, Bioactive peptides, Stress, Agricultural waste, Biostimulants