Abstract: This study assessed the influence of government policies on sustainable agriculture at the Nasho Irrigation Project in Kirehe District, Rwanda. A quantitative, cross-sectional correlational design was used. The target population was 150 farmers, extension agents, energy policymakers, government entities and project implementers, from which a stratified random sample of109 was drawn using Yamane’s formula. Structured questionnaires measured policy support, financial incentives, support programs and promotion initiatives on a five-point scale, and 106 were returned (97.2%). The instrument was reliable (Cronbach’s alpha = 0.916), and data were analyzed in SPSS using descriptive statistics, Pearson correlation and multiple regression. Respondents agreed moderately that government interventions encourage solar irrigation (means 3.19 to 3.35). Government policies correlated strongly with sustainable agriculture (r = 0.740, p < 0.01) and had a positive, statistically significant effect in the joint model (beta = 0.178, p = 0.036), which explained 73.4% of the variance. The effect of policy was smaller than that of extension services and technology awareness. The study concludes that supportive policy is a necessary but insufficient enabling condition. It recommends expanded subsidies, low-interest credit, demonstration farms and regular monitoring, delivered together with extension and awareness programs.