Assessing teaching performance is a contentious issue in current educational policy in many countries. In Chile, a national, standards-based, multi-method, mandatory teacher evaluation system has been in place since 2003 to assess the performance of about 70, 000 public school teachers from pre-school to high school and adult education. The Chilean system combines formative and summative purposes and uses four instruments: a structured portfolio, a peer interview, supervisor questionnaires, and a self-assessment. In this paper we analyze the Chilean system as a case of interest regarding some controversial issues in teacher evaluation today. To this end we describe the system's political background, implementation process and results. We put a special focus on the development and evolution of its evaluation instruments; we discuss their strengths and limitations and review the research evidence regarding their validity and reliability. Finally, we reflect on the Chilean experience in terms of the insights it can provide into teacher performance assessment for an international audience.