This chapter describes networking for education for sustainable development within the Austrian ECOLOG-schools network. It discusses theoretical concepts of Education for Sustainable Development and school development from an Austrian perspective, as well as networks in education in general and the organization of the ECOLOG-network in particular. Furthermore, the international Environment and School Initiatives (ENSI) network is described as an influential stimulus for the development of ECOLOG. Based upon these foundations, the concept and results of evaluation studies of ECOLOG-schools are described and reflected. The impact of ECOLOG on the developments in environmental education/education for sustainable development in Austria is described and reflected. The paper concludes with a summary of the evaluation process and with an outlook for the future development of the network.