Global economic development is closely linked to energy use, yet rising fossil-fuel consumption has intensified carbon dioxide (CO2) emissions and environmental degradation. This study examines the long-run and short-run relationship between renewable energy consumption and financial development in South Africa over the period 1990–2024 using the Autoregressive Distributed Lag (ARDL) model. The variables included are renewable energy consumption, financial development, economic growth, capital formation, and inflation. Financial development is proxied by credit extension, monetary aggregate (M3), and stock exchange transactions. The results confirm the existence of a long-run equilibrium relationship among the variables. Financial development has a positive and statistically significant effect on renewable energy consumption in both the short run and long run, indicating that deeper and more efficient financial markets improve access to capital for renewable energy projects. Economic growth and capital formation also promote renewable energy expansion, while inflation negatively affects renewable energy consumption by raising investment costs and uncertainty. The study recommends that the government should promote an environmentally friendly economy by expanding green finance instruments, introducing tax incentives and subsidies for clean energy investments, and strengthening regulatory certainty. Public-private partnerships should be encouraged to mobilise private capital for solar, wind, and biomass infrastructure. Maintaining macroeconomic stability and improving financial inclusion are also essential for achieving sustainable growth, energy security, and climate change mitigation in South Africa.