This dissertation is a mixed-methods study designed to examine relationships among the following constructs: teacher self-efficacy, teacher-student relationships, trust, student engagement, and student social capital. A conceptual framework was created in reference to the literature relating to each primary construct. Furthermore, six research questions were established to guide the research methodology and the study's overarching questions: "What are upper elementary (grades 3-5) teachers' perceptions of teacher self-efficacy, teacher-student relationships, trust, student engagement, and student social capital in high-performing schools and low-performing schools? How do these perceptions differ among upper elementary (grades 3-5) teachers in high-performing schools and low-performing schools?" The study used a large school district in Louisiana encompassing 43 elementary schools, grades K-5. Only teachers were administered the survey, which included three measures, and six open-ended survey questions. Data analyses included descriptive statistics and demographics for the sample, descriptive statistics for each item, t tests to compare two groups on measured variables, bivariate correlations among all subscales of each measure, and thematic analysis of open-ended survey questions. Major findings of the study indicated: (1) teacher self-efficacy and teacher-student relationships have the strongest relationship when considering the study constructs of teacher self-efficacy, teacher-student relationships, and trust; (2) upper elementary teachers' perceptions of the trust construct, revealed the greatest statistically significant difference between low and high performing schools; (3) upper elementary teachers perceive student peer collaboration, contingent on positive student social interactions, to be one of the most highly effective forms of student engagement; (4) upper elementary teachers believe relationship building is a vital component of all study constructs related to student achievement. These major findings have several implications for theory, leadership and practice, and future research. [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.]