Teachers who work in isolation may experience low self-efficacy. Research shows an association between high self-efficacy and positive outcomes for teachers, such as teacher longevity and higher instructional effectiveness. While some studies have suggested that a collaborative teaching environment can decrease teacher attrition and increase student achievement, little is known about how collaboration impacts teaching self-efficacy. The purpose of this qualitative single case study was to describe teacher perceptions about the impact of teacher collaboration on teacher self-efficacy at a charter high school. Bandura's self-efficacy theory formed the conceptual framework for the study. Using teacher interviews, observations and documents related to teacher collaboration, this study investigated the experiences and perceptions of six teachers. Data were analyzed using line-by-line coding, incident-by-incident coding, category construction, and explanation building to discover patterns, themes, and relationships related to Bandura's four sources of efficacy development. The key finding was that with administrative support, student-centered teacher collaboration resulted in an increase in teaching self-efficacy. A key recommendation is for school leaders to provide time for teachers to engage in student-centered collaborative efforts. Implications for social change include fostering instructional collaboration that can result in more increased teacher effectiveness and improved student academic achievement. [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.]