"The Leader in Me" (Covey, 2008) is an approach to fostering social and emotional learning that has been adopted by more than 3,000 schools across the globe, but which has received relatively little empirical attention. Grounded in the seven habits from Stephen Covey's (1989)" The 7 Habits of Highly Effective People", the school-based program "The Leader in Me" supports schools in fostering social and emotional learning and empowering students to take on leadership roles in their school. Using a mixed-methods approach, this study examines the social and emotional learning of elementary school students attending six public elementary schools that began implementation of "The Leader in Me" in 2014-15 in comparison to their peers at six structurally and demographically similar comparison schools within the same school districts. The survey and interview data from participating schools are analyzed through the lens of two main conceptual frameworks: social and emotional learning and youth voice. Quantitative results indicate that Leader in Me students demonstrated a significant, negative treatment time effect for eight of the thirteen measures, and a significant, negative treatment effect for one additional measure, as compared to students attending the matched comparison schools. Three of these measures are related to social and emotional learning, four are related to youth voice, and two are related to overall teacher and school support. Qualitative results reveal that while some students spoke of the 7 habits in ways that demonstrate awareness and application of social and emotional competencies, they also had varying levels of understanding of the habits themselves. Similarly, while some students and teachers spoke of the ways that "The Leader in Me" fosters youth voice and empowerment, other qualitative data suggest that the program is having the opposite effect, and that students are defining youth leadership as compliance. Findings from this study highlight the following recommendations for social emotional and youth voice reform efforts: a clearly communicated implementation framework at the classroom and school level accompanied by an aligned fidelity rubric; the adoption of an action-reflection cycle that includes both teacher and student perspectives; and the awareness of, and active preparation for, inherent power dynamics in 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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]