Water scarcity is a real challenge in the Mediterranean countries such as Tunisia. Currently, in Tunisia, about 80% of the resources are allocated to the agricultural sector. The irrigated areas are estimated at 420000 ha, consist of 220000 ha of public perimeters and 200000 ha of private perimeters. In arid and semi-arid regions of central and southern Tunisia, the cultivation of the olive tree (Olea europaea L.) is an important widespread activity, mainly due to its great adaptability to the conditions of water deficit and its nutritional value. Olive oil is a susceptible product, its quality and organoleptic characteristics can be influenced by several factors from harvest to storage, such as irrigation. The results obtained in the present study allowed classifying the monovarietal oils samples in the extra virgin category. In general, the impact of irrigation is very remarkable, mainly in the reduction of the pigments, alpha tocopherols, oleic acid, and total phenol compound contents. This decrease recorded in these various parameters is found in olive oil produced from trees grown under daily irrigation in Ksar Ouled Debbab. The data registered in this present work revealed that oil composition and quality could be directly affected by irrigation. Our results can give useful indications for explaining more the relation between irrigation strategies and olive oil quality: Qualitative and quantitative compositional analysis showed that several oil parameters significantly decreased in the freshwater irrigated plot more than the rainfall plot.