The invasion of Rohingya refugees has greatly influenced the landscape of the Cox’s Bazar district, especially in designated resettlement areas like the Kutupalong camp, one of Bangladesh’s largest refugee camps located in Ukhia Upazila (or Sub-District). To address sustainable groundwater management in this area, this research utilizes Geographic Information System (GIS) and Analytic Hierarchy Process (AHP) methods to assess groundwater possibility in Ukhia Upazila (or Sub-District), Cox’s Bazar, with a focus on the post-settlement scenario, following the future groundwater hazard potential due to the Rohingyas’ invasion. By examining 11 crucial factors that impact groundwater potential—such as elevation, geology, rainfall, slope, aspect, drainage density, proximity to rivers, soil type, land use/land cover, NDVI (Normalized Difference Vegetation Index), and lineament density—the study assigns weights to these factors using Saaty’s 9-point scale. Through AHP’s eigenvector technique, elevation is identified as the most influential factor (24%), followed by proximity to rivers (20%), rainfall (16%), and drainage density (12%), with other factors showing less impact. The study classifies groundwater potential zones into four classes: low, moderate, high, and very high—covering 35.19 km2, 156.16 km2, 68.99 km2, and 1.55 km2, respectively. Validation using the Area Under the Curve (AUC) and the Receiver Operating Characteristic (ROC) methods yields an AUC score of 0.827, indicating strong model performance in predicting groundwater potential. The results provide a valuable spatial overview of groundwater potential and backup-informed policymaking for water resource planning and administration in Ukhia Upazila, in view of the future hazard potential.