Population aging is also visibly progressing in developing countries and is likely to become a more serious policy issue in the near future. Because of the faster rate of aging, developing countries tend to be less prepared for a large elderly population, especially since their fast expanding social security system may neither be adequate nor sustainable. In an effort to promote Sustainable Development Goals (SDGs), G20 member countries’ systematic support will be necessary for the development of an effective and sustainable social security system in developing countries. In this regard, G20 members need to (i) support the establishment of a framework for developing countries to assess the effectiveness and efficiency of their system, and (ii) provide technical support to developing countries in developing and implementing medium to long-term frameworks.