This dissertation is a quantitative study which presents a conceptual framework which views schools as learning communities. The study focuses on relationships among professional learning communities, teacher self-efficacy, and collective efficacy. The researcher also explored teacher perceptions of these three constructs. The specific purpose of this study was to conduct research on: (1) schools as learning communities and the influence of professional learning community dimensions on teacher and collective efficacy at the elementary, middle school, and high school levels; (2) the influence of efficacy of teachers and collective efficacy in schools classified as high poverty and low poverty, and (3) the influence of professional learning communities, teacher self and collective efficacy in TAP and Non-TAP schools. Thus, the overall two-part question for this research study is: (1) What relationships exist among the constructs of professional learning communities, teacher self-efficacy, and collective efficacy? and (2) How do these relationships manifest within various school structures including: (1) elementary, middle, and high levels of school; (2) TAP and Non-TAP schools; and (3) high poverty and low poverty schools? [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.]