In recent decades, changes to federal and state accountability policy and related teacher evaluation systems occurred in the United States with minimal input from two of the largest groups of stakeholders impacted: principals and teachers. For this case study, I explored principals' and teachers' perceptions of their experiences with the Texas Teacher Evaluation and Support System (T-TESS), specifically the role of leadership practices and use of the evaluation rubric as a policy tool within an evaluation process. The study took place at one elementary school. Teachers perceived the evaluation process as carrying out its intended purpose of improving instruction through professional growth. Principals and teachers viewed the teacher evaluation system and the teacher evaluation rubric, a policy tool designed to facilitate and inform the processes and practices used to improve instruction in their districts and schools, as effective. Important district-level decisions also impacted how principals and teachers perceived the T-TESS. District-level decisions included policy related to frequency of required observations, methods of including student performance data, decisions related whether to issue a single rating or multiple ratings, and evaluation of specialized teachers. School-based leadership behaviors and practices were also found to influence teachers' perceptions related to the effectiveness of teacher …