This study examined the implementation of Hybrid Grouping at Angel Elementary School. The Hybrid Grouping model consisted of three elements, achievement grouping, departmentalization and self-contained classes. The data collected allowed participants (n = 20) to share their perceptions of the leadership of the school and its relationship to the implementation of Hybrid Grouping and school climate. This mixed-methods study used data from the Angel Elementary PRIDE Survey, Angel Elementary Teachers Perception Survey, Interviews, and Alabama reading and math testing data. The framework of this study was developed based on three key constructivist theories social constructivism posited by Vzgostsky (1978), cognitive constructivism formulated by Jean Piaget (1952, 1954, 1962) and pragmatism, as delineated by Dewey (1916/2012). These three theorists suggested the social interaction of children with their environment and participating in practical, hands on activities were critical to their social, cultural, and personal development. The results of this study of Hybrid Grouping showed that significant change occurred in student performance from the pre post implementation test on ARMT scores. The results suggested that when Hybrid Grouping is implemented properly, student achievement increases. However, the 4th grade students (3d) had less positive than negative differences in the ARMT Reading scores and 6th grade students (3f) had less positive than negative differences in the ARMT Mathematics. The analysis of teacher interviews supported the findings from the quantitative data. Four themes were gathered from the interviews that aligned with the surveys and the ARMT scores. The four themes were: Teaching to Their Strength, Leaders' Role in Developing People, School Culture, and Innovation for Student Growth. Two broad conclusions were drawn from the research. First, the teachers perceived school leadership as having a positive impact on school climate. Secondly, teachers perceived that a shift occurred in the organizational climate during the successful implementation of this innovative model. Significant student learning outcomes occurred in concert with this climate shift. Recommendations for practice and for further research were provided. [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.]