Some 7400 schools belong to the global network of UNESCO's Associated School Project Network. They are committed to promoting ideals such as human rights, intercultural understanding, peace and environmental protection. This study is based on an extensive review undertaken in 2003. It discusses the origins and analyzes the achievements of the Associated School Project Network in bringing change to schools, communities and national policy. The analysis employs a variety of models of educational innovation and reform in order to assess the horizontal and vertical impact of the Associated School Project Network. It draws general conclusions on the usefulness of such networks for intercultural learning and educational and social change. Key issues include the commitment of stakeholders; the treatment of culturally sensitive issues; cultural interpretations of certain subjects; the value of horizontal networks; and the difficulty of achieving vertical impact on national policy-making.