Geotourism is a sustainable form of tourism that emphasizes the geological and geomorphological characteristics of the earth, fosters an appreciation for and commitment to cultural preservation and environmental conservation, and benefits the development of local communities. To develop geotourism activity in a certain region, assessing its geotourism potential is a prerequisite. The present study aims to develop a geotourism site suitability map for the Eastern Duars region, West Bengal, India, through the GIS-Based Fuzzy Analytical Hierarchy Approach (F-AHP) and Analytical Hierarchy Process. Based on the results of FAHP, a suitability map of geotourism has been prepared. It has been observed that about 6.30% of the study area is under highly suitable zones, 16.10% are suitable zones, 77.29% are marginally suitable zones, and 0.31% are not suitable zones. No proper recognition of the existing geosites and the lack of planned geotourism infrastructure is the reason for such a result. Finally, the result was validated by Receiver Operating Characteristic (ROC) and Area Under Curve (AUC). The values of the AUC value of ROC were 0.983 and 0.966 for F-AHP and AHP, respectively, which signify reliability for both methods. The findings suggest that the northern, north-eastern and north-western portions of the study area covering the areas of Kalchini, Madarihat-Birpara, and Kumargram are most suitable for geotourism. The selected criteria and the layers developed for the study can help the policy-makers to determine the ideal locations for the development of different infrastructures and plan accordingly so that the natural environment and tourism activities can co-exist and the essence of sustainable livelihood can be preserved in the Eastern Duars region. However, along with the planning, educating the locals and promoting the geosites about their significance is also very necessary for the recognition of the study area. Thus, the present study is novel in terms of geotourism site suitability with the GIS-based MCDM method in the Eastern Duars region of West Bengal, India.