Implementation of state and federal high-stakes accountability measures such as end-of-course tests (EoCTs) has contributed to increased teacher stress in the classroom, decreased teacher creativity and autonomy, and reduced effectiveness. Prior research focused primarily on the elementary and middle school levels, so this study sought to examine the perceptions of teachers at the secondary school level. The purpose of this qualitative, single-case study was to examine the perceptions of secondary teachers about the impact of performance-based accountability on their sense of efficacy. Driven by a social constructivist paradigm, the research question focused on the perceptions of 9 secondary teachers about the impact of performance-based accountability. Report card data, average yearly performance data, interview responses, and EoCT data for the 2011-2012 school year were collected. Inductive analysis was used to codify teachers' perceptions, which showed that an increased focus on test data negatively impacted teachers' sense of efficacy. Findings revealed 4 domains regarding teacher experiences: (a) increased stress, (b) increased frustration, (c) growing distrust of the test and the institutions surrounding the test, and (d) loss of respect for their professional judgment in their classrooms. This study calls into question the use of test data to evaluate teacher effectiveness. Findings may contribute to positive social change by informing the current debate on the use of test data in evaluating teachers, and highlighting research indicating that teachers with a greater sense of efficacy may be more effective in the classroom. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]