The international community faces two major challenges: securing stable energy supplies and achieving carbon neutrality. Concerns about energy security that aroused due to the oil crises in the 1970s are no longer limited to the stable supply of fossil fuels. The concept of energy security is changing in line with the need for transition from fossil fuels to clean energy. As energy prices have soared due to the recent Russia-Ukraine war, major countries are actively pursuing related policies and external cooperation to diversify their energy supply chain and decarbonize their economic structures. In order to appropriately respond to these challenges, continuous efforts are needed to gradually reduce the use of fossil fuels and in crease the use of clean energy in the medium to long-term. In particular, as the proportion of power generation from variable renewable energy sources increases, maintaining the stability of the power grid becomes a more important task. Demand for minerals essential for clean energy related technologies is expected to increase, however, production of these minerals is concentrated in specific countries. Major concerns related to carbon neutrality or clean energy investment include whether sufficient investment is being made, whether funds are being directed to countries or sectors in urgent need of financial support, and how to induce private investment through public funds. Accordingly, our study analyzed energy security from the perspective of energy transition, and derived key issues and notable cases of international cooperation to ensure energy security and carbon neutrality. Based on our findings, we suggested policy implications for Korea.