The accreditation systems of higher education institutions and/or programmes are becoming a policy measure used to find a balance between their autonomy and public assurance concerning the quality of the qualifications they award. This article analyses, from the point of view of this balance of power, the process of development of the Portuguese accreditation system aimed at providing public assuranc e that initial teacher education programmes are more driven by social demand, namely by the changing school education needs. This was a political and cultural process rather than a merely rational and technical one. Thus the emergence of the need for, and possibility of, external pressure upon higher education institutions is related to the evolution of several social factors. On the other hand, the implementation of the accreditation system means a significant change for these institutions which implies new practices and comes into conflict with some of their values and with power sharing within and among them and with society. For these reasons a strategy of wide participation of significant stakeholders was deemed more suitable for the formulation, adoption and implementation of this new public policy. The way in which Campos: Teacher Education Acreditation in Portugal 2 Government, the accreditation body and the significant stakeholders exercised their power in this process influenced the characteristics of the system, the rhythm of its implementation and t he abrupt governmental decision to put it on stand by, until now.The accreditation systems of higher education institutions and/or programmes are becoming a policy measure used to f ind a balance between the autonomy of these institutions and public assurance concerning the quality of the qualifications they award. This article (Note 1) analyses, from the point of view of this balance of power, the development of the Portuguese system for the accreditation of initial school teacher education programmes (Note2). It starts by making a short reference to the higher education accreditation movement, especially in the field of teacher education, and by pinpointing the role of an accreditation system within the process of public certification of qualified teacher status. The second section outlines the historical and social process leading to the social awareness that there was a social issue urging a new policy measure. T he third characterises the structural and functional elements of the system developed. The description of the strategy chosen for the formulation, adoption and implementation of this policy appears in the fourth section. Finally, the way social actors exerted their power in t he process of development of this policy is highlighted and some lessons are drawn from it.