This article explores a case of shifting leadership responsibility for teacher evaluation. Peer Assistance and Review (PAR) formally involves teachers in the summative evaluation of other teachers--although the boundaries of the involvement are often vague. Since teacher evaluation has traditionally been the domain of school principals, involving teachers in teacher evaluation raises questions about how those faced with the new role make sense of it and enact it. The article draws on theories of professions, organizations, and institutions to examine the implementation of PAR in one large urban school district. Findings suggest that, despite positive sentiments about the policy across stakeholder groups, those involved wanted principals to remain a central figure in the evaluation of teachers in PAR. Education's hierarchical norms, the difficulty of conducting evaluations, district leadership, and program ambiguity are identified as challenges to distributing leadership. (Contains 4 tables and 21 notes.)