Various approaches have been advocated and practiced to address sustainable development. Among these, education has been recognized as one of the key measures to achieving sustainability. In Nishinomiya, Japan, education for sustainable development (ESD) has been established through the Learning and Ecological Activities Foundation for Children (LEAF), a nonprofit organization whose activities have been adopted by the Ministry of the Environment as the model for Japanese ESD projects nation-wide. LEAF aims to establish mutual learning programs through various types of activities. Through an examination of LEAF initiatives, key elements for achieving sustainable development are explored and analyzed in relation to the UNESCO framework for implementing ESD (UNESCO, 2003). The paper suggests that a mutual learning environment is a key element in achieving sustainable development. (Contains 1 note.)