The paper discusses the process whereby a system of teacher evaluation was established in Chile through a lengthy and complicated process of negotiations between the three main institutions concerned: the Teachers' Union, the Association of Chilean Municipalities (managers of the public school system) and the Ministry of Education. The process is examined in the light of discussions centred on teacher accountability and tensions between the concepts of formative and summative teacher performance evaluation. In order to understand the issues that arose along the process the article provides historical background information about conflicts surrounding teachers during the Military Government (1973-1990) as well as a discussion on how the different parties involved incorporated the different perspectives on teacher accountability and evaluation of teacher performance that are found in the literature and policy discussions in other geographical contexts. In its conclusion, it focuses on the importance of time, consultations and negotiations in order to reach the implementation of a system that is both appropriate and feasible for the agreed purposes.