Abstract: In arid regions, rainfall is scanty and groundwater is the main source to fulfil the domestic and agricultural needs. This study aimed to assess the groundwater quality using Geographical Information System (GIS), hydrogeochemical investigation and accurate spatial distribution of water quality index (WQI) and electrical conductivity (EC). A total of 130 groundwater samples were collected from 65 wells in El Outaya basin (Algeria), and they were analyzed for major physicochemical parameters over two seasons: first after dry season in 2017, second after wet season in 2018. Prediction maps of WQI and (EC) for both periods were created using ordinary kriging (OK) method in a GIS environment. Cross validation technique was applied to check the accuracy of the prediction maps of WQI and EC. The results show that (Na+ +K+)?(Cl- +SO4-2) and (Ca2+ +Mg2+)?(Cl- +SO4-2) are the major hydrochemical facies as defined in Piper trilinear diagram. Saturation indices indicate evaporitic minerals dissolution (anhydrite, gypsum and halite) and carbonate minerals precipitation (aragonite, calcite and dolomite). WQI depicts that the majority of groundwater samples fall within the �very poor� and �unsuitable� for drinking categories. EC and sodium adsorption ratio (SAR) classified using Reverside diagram point out a high to very high risk of groundwater salinity and medium to high risk of alkalinity for soil salinization. The WQI and EC data showed a normal distribution based on Shapiro-Wilk test. Cross validation indices such as mean error (ME) indicate accurate prediction results, where, for WQI predictions ME values are -0.014 and 0.104, and for EC predictions ME values are 0,009 and 0,013 in dry and wet seasons, respectively. The prediction maps show almost the same overall spatial distribution of WQI and EC for dry and wet seasons. The groundwater quality was accurately assessed using GIS and OK method, which can be helpful for groundwater managers and decision makers in arid areas.