Water is the most widely limiting factor for plants distribution, survival and agricultural productivity, their responses to drought and recovery being critical for their success and productivity. Olea europaea L. is a well-adapted species to cyclic drought events, still at considerable expense of carbon reserves and CO 2 supply. To study the role of abscisic acid (ABA) as a promoter of drought adaptability, young potted olive trees subjected to three drought-recovery cycles were pre-treated with ABA. The results demonstrated that ABA pre-treatment allowed the delay of the drought effects on stomatal conductance (g s ) and net photosynthesis (A n ), and under severe drought, permitted the reduction of the non-stomatal limitations to A n and the relative water content decline, the accumulation of compatible solutes and avoid the decline of photosynthetic pigments, soluble proteins and total thiols concentrations and the accumulation of ROS. Upon rewatering, ABA-sprayed plants showed an early recovery of A n . The plant ionome was also changed by the addition of ABA, with special influence on root K, N and B concentrations. The improved physiological and biochemical functions of the ABA-treated plants attenuated the drought-induced decline in biomass accumulation and potentiated root growth and whole-plant water use efficiency after successive drought-rewatering cycles. These changes are likely to be of real adaptive significance, with important implications for olive tree growth and productivity.Olive tree (Olea europaea L.) is a woody species which grows under the typical Mediterranean semi-arid conditions, a region already affected by multiple environmental constraints factors, and particularly susceptible to climate change, being expected higher temperatures and shifts in the precipitation patterns, leading to higher evaporative demand and lower soil water availability [4]. Although olive is a crop well-adapted to harsh conditions, water deficit has negative repercussions on water relations, carbon assimilation, oxidative pathways, nutrient uptake and biomass accumulation [1,[5][6][7][8][9][10]. Moreover, the adaptation mechanisms adopted by this species against drought stress are activated at the expense of carbon reserves and may be detrimental with the increased duration and intensity of stress. The increasing consciousness regarding the nutritional value of olive oil has enhanced the demand for this product and, thus, it is crucial to increase olive trees ability to conserve and use the scarce available water and the low and unexpected rainfall during the summer season.Abscisic acid (ABA) is a well-known plant stress hormone, being assumed as a potential mediator for induction of drought tolerance in plants [2]. Under drought, ABA elicits two distinct responses, where the earliest and most rapid is stomatal closure, which minimizes the water loss through transpiration. Further, ABA gradually increases hydraulic conductivity and promotes root cell elongation, enabling the plant to recover, and inducing the a...