In this study, groundwater quality in Sunamganj of Bangladesh was studied based on different indices for irrigation and drinking uses. Samples were investigated for sodium absorption ratio, soluble sodium percentage, residual sodium carbonate, electrical conductance, magnesium adsorption ratio, Kelly’s ratio, total hardness, permeability index, residual sodium bi-carbonate to investigate the ionic toxicity. From the analytical result, it was revealed that the values of Sodium Adsorption Ratio indicate that ground water of the area falls under the category of low sodium hazard. So, there was neither salinity nor toxicity problem of irrigation water, so that ground water can safely be used for long-term irrigation. Average Total Hardness of the samples in the study area was in the range of between 215 mg/L at Tahirpur and 48250 mg/L at Bishamvarpur. At Bishamvarpur, the water was found very hard. Average total hardness of the samples was in the range of between 215 mg/L at Tahirpur and 48250 mg/L at Bishamvarpur. At Bishamvarpur, the water was found very hard. It was shown based on GIS analysis that the groundwater quality in Zone-1 could be categorized of “excellent” class, supporting the high suitability for irrigation. In Zone-2 and Zone-3, the groundwater quality was categorized as “risky” and “poor” respectively. The study has also made clear that GIS-based methodology can be used effectively for ground water quality mapping even in small catchments.