The installation of an olive mill wastewater (OMW) disposal site without well-defined standards and constraints may cause undesirable long-term effects on soils and groundwater. In Tunisia and other developing countries, there are no solid waste control regulations to control the location selection of disposal sites. In this study, the OMW disposal site criteria established in Greece, Turkey, and China’s regulations were used to select the best location for the OMW disposal site in the Sidi Bouzid region of Tunisia. The multi-criteria analysis was performed using a geographic information system (GIS) combined with the different functions of the fuzzy set method for suitability criteria. The analytic hierarchy process (AHP) was used to assign the weight of selected criteria and the weighted linear combination (WLC) aggregation method is displayed to create the final OMW disposal site. The obtained results show that the selection of suitable OMW disposal sites is based on different norms, given the spatial differences of the selected areas. The final decision is based on the selection of the strictest solid waste control regulations which takes into consideration environmental and socio-economic effects.