City of Gaziantep, which has many economic, industrial, and social attractions in its region, has witnessed a rapid growth in the last two decades. A spatial modeling system that could provide regional assessments of future development and explore the potential impacts of different regional management scenarios would be useful for the future health of the cities. Therefore, SLEUTH Model was used in this study. SLEUTH is a pixel-based cellular automaton model which has been applied to several cities worldwide and has also been applied to the city of Gaziantep. The model was calibrated using historic time series of built-up areas derived from remote sensing imagery, and future growth was simulated for the year 2040 predicting three different policy scenarios: (1) unmanaged growth with no restrictions on environmental areas such as agriculture and forest, (2) managed growth with moderate protection, and (3) managed growth with maximum protection on environmental areas. The results showed that fertile agricultural land is the most affected natural resource in Gaziantep. 14.300 ha of agricultural land is predicted to be lost by the year 2040 with the unmanaged growth scenario, however, about 8.000 ha of that is predicted to be protected with managed growth scenario in Gaziantep. Finally, it's aimed that the results would be of great potential use for the planners.