This study investigates the influence of climatic parameters and river flow on electricity generation at Jebba Dam, Nigeria. Climatic factors such as rainfall, temperature, and evaporation directly affect reservoir inflow and outflow, which in turn impacts hydropower generation. Secondary data on climatic parameters, reservoir inflow and outflow, and hydropower production from Mainstream Energy Solution Limited in 2018 were analyzed using averages, with results presented in graphs and charts. The findings indicate that power generation at Jebba Dam peaked from July to December, with the highest generation occurring in November at 432.5 MWh. Reservoir inflow and outflow also increased during this period, reaching their highest values in September, with inflow and outflow recorded at 4860 m³/sec and 4858 m³/sec, respectively. Rainfall patterns showed a marked increase from May to November, with September experiencing the highest rainfall at 330.4 mm. The highest temperature of 36°C occurred in both February and November, while March recorded the highest evaporation rate of 25 m³/sec. The study highlights the significant effects of these climatic factors on reservoir flow and hydropower generation, emphasizing the importance of considering climate change in the management of hydropower resources. The findings suggest that the government must urgently address the challenges posed by climate change to ensure the sustainability of hydroelectric power generation in Nigeria.