The importance of assessing groundwater quality is unassailable in our day and age. This assessment determines the classification of water quality for different purposes. Recent advancements in Geographic Information System techniques have allowed hydrologists to apply various approaches for more effective groundwater quality prediction and management. In this chapter, our case study was groundwater in Kanchanaburi Province, Thailand. Twelve groundwater parameters were estimated for mapping groundwater quality based on the entropy water quality index. Inverse Distance Weighting and Kriging were employed to prepare layers of groundwater parameters based on the normal distribution test. The results indicated that approximately 97.3% of the area was classified as good and very good groundwater for agricultural and drinking purposes. The coefficient of determination, root mean square error, and mean absolute error of the groundwater quality map were 0.82, 0.07, and 0.05, respectively. Polluted groundwater locations (groundwater quality from very poor to moderate levels) were identified in some agricultural areas. The findings of this study can serve as a reference for global groundwater quality assessments using geospatial techniques.