A comprehensive examination of siphon turbine design and optimization using the response surface methodology (RSM) is presented in this study. The goal was to improve the turbine efficiency by analyzing the impact of two key factors: the number of blades (n) and the ratio between the hub diameter (d) and the outer diameter of the rotor (D), (d/D). The application of RSM facilitated the creation of a response surface, unveiling the optimal combination of factors for maximizing efficiency. The novelty of this article lies in utilizing the response surface methodology to refine the design of existing turbines, resulting in a more streamlined and effective design process tailored to the specific requirements of the installation. The findings indicated that rounding the number of blades to 5 and maintaining a constant d/D ratio of 0.35 yielded the highest efficiency (41.4%). Experimental validation was carried out and the accuracy of the optimized design was demonstrated, paving the way for practical applications in renewable energy solutions. Therefore, the effectiveness of RSM in optimizing siphon turbine designs is supported since valuable insights are provided for enhancing the energy efficiency in small-scale hydropower systems. The investigation contributes to the development of sustainable and clean energy technologies, showcasing the potential of siphon turbines in harnessing low-head water sources for power generation.