This thesis is concerned with the extent to which new teacher evaluation policies and practices in Japan are about controlling teachers or represent opportunities for authentic professional development. It seeks to examine how the new teacher evaluation policies are embedded within the wider policy formation, what perspectives teachers have on the new policies and what their experiences are, and how the new teacher evaluation policies are actually being enacted in schools. The thesis uses a range of methods to explore these concerns. For the purpose of macro analysis of the new teacher evaluation policies, it examines both primary and secondary documentation around policy development. For studying the impact of the policy in schools, it draws on data from a national survey and in-depth interviews with a sample of teachers and head teachers. In this way, it employs a mixed methods approach in which quantitative data is used to provide a general picture of how teachers experience and perceive the new teacher evaluation policies and practices and qualitative data is used to provide the depth of analysis required to look at the nature of performativity in schools. The concept of performativity has been central to the overall investigation. The study argues for a particular reading of performativity — a work through, as opposed to work upon, perspective. This analytical lens illustrates how the new teacher evaluation policies have played a role in producing or reinforcing the mutually policing relations that lead to destabilisation of teacher’s identities. This thesis concludes that the enactment of new teacher evaluation policies has had significant indirect impacts on teachers and teachers’ work by affecting modes of school management and teachers’ relationships. By illustrating the usefulness of the work through perspective of performativity, it has enabled theorizing of performativity to advance. It also illuminates both congruence and variance between teacher evaluation policies as enacted in Japan and other countries. Japan’s teacher evaluation is no less effective as a measure of political control than its counterparts in other countries, but it can work in a more subtle way: teacher evaluation affects, repositions, and reconstructs teachers’ work and identities through affected relationships as mentioned above. This implies that teachers as well as policymakers should develop a more broad, macro-political and critical perspective on teacher evaluation.