This concurrent multi-phase mixed methods study investigated whether indicators of Social Cognitive Theory could be observed in Grades 3-5 classrooms and if these indicators could be used to describe teacher effectiveness in high poverty schools. The conceptual framework drew upon Bandura's (1997) measurement of the individual self-efficacy of students and the collective teacher efficacy of the organization to study the level of agency and self-efficacy cultivated by the teacher and students in the classroom environment. Major findings confirmed a correlation between self-efficacy and student outcomes in ELA and mathematics. Looping, the practice of students being paired with the same teacher for multiple years, was also a significant factor. Agentic and self-efficacious student behaviors were observable in classrooms. An observation tool developed over the course of the study was found to be mostly reliable and had internal consistency with the exception of one subscale in mathematics. Preliminary evidence suggests there are observable cultures of student agency and self-efficacy in classrooms, but the sample group and scope of the study were limited. Further research in this area is warranted. [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.]