The purpose of this study was to explore how teachers' perceptions and professional development experiences influenced their sense of efficacy regarding their impact on student learning with diverse populations of students. Data collection for this study was conducted with a mixed methods approach. The Teacher Self-Efficacy Scale was the instrument used to gather quantitative data from 32 participants. An open-ended questionnaire and an adapted version of the Collective Efficacy Scale produced qualitative data from five participants. Four themes emerged: environmental challenges, teacher preparation, instructional practice, and support. The four themes and their subthemes correlated with previous research, suggesting that student engagement, instructional strategies, and classroom management consistently influenced teachers' sense of efficacy to impact student learning. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]