With less than 3% of agricultural cropland under irrigation, subsistence farmers in Uganda are dependent on seasonal precipitation for crop production. The majority of crops grown in the country—especially staple food crops like Matooke (Plantains)—are sensitive to the availability of water throughout their growing period and hence vulnerable to climatic impacts. In response to these challenges, the Government has developed an ambitious irrigation master plan. However, the energy implications of implementing the plan have not been explored in detail. This article attempts to address three main issues involving the nexus between water, energy, crop production, and climate. The first one explores the impact of climate on rain-fed crop production. The second explores the irrigation crop water needs under selected climate scenarios. The third focuses on the energy implications of implementing the irrigation master plan. We attempt to answer the above questions using a water balance model for Uganda developed for this study. Our results, developed at a catchment level, indicate that on average there could be an 11% reduction and 8% increase in rain-fed crop production in the cumulatively driest and wettest climates, respectively. Furthermore, in the identified driest climate, the electricity required for pumping water is expected to increase by 12% on average compared to the base scenario.