From an educational equity perspective, all students need to have appropriate learning opportunities that are close to their own cultural contexts (e.g., families and communities). Based on the transformative social-emotional learning (SEL) framework, the mixed-methods study explored how culturally relevant reading experiences can be longitudinally linked with underserved students' social-emotional and academic development. Specifically, this study explored changes in underserved students' prosocial self-efficacy and reading skills across multiple years of involvement with a culturally relevant reading program at Freedom Schools. The multicultural reading program at Freedom Schools is rooted in culturally relevant pedagogy and SEL to empower racially-minoritized students to make a difference. The purpose of the six-week summer camp is to help underserved students maintain their reading skills during the out-of-school summer period. To explore possible sustainable learning outcomes from experiences at Freedom Schools, this study focused on targeted participants who participated in the Freedom Schools camp for at least two years (i.e., returning students in 2016 through 2019). The purpose of the study was to investigate students' prosocial self-efficacy and reading skill outcomes over time. From the four years of annual data from Freedom Schools participants, I identified data with parental consent for a total of 50 returning students. For the quantitative analysis, I investigated returning students' individual change patterns in prosocial self-efficacy (n = 38) and reading skills (n = 22). To support the results from the individual change patterns, I also analyzed 16 interviews from eight returning students; each student participated in two interviews that were collected during different summer years of Freedom Schools. According to the descriptive results of this study, within the summer program period (i.e., during the six-week), returning participants at Freedom Schools showed descriptive positive changes in their prosocial self-efficacy in their first camp (67.7%) and their second camp (57.6%); however, between the first and second camps, their prosocial self-efficacy changes varied across individuals. The majority of returning participants showed descriptive positive reading changes. For example, returning students descriptively increased or maintained reading skill levels in their first camp (at least 85% of participants in all reading subfactors) and in their second camp (at least 80% of participants in all reading subfactors). The summer program aimed to prevent summer reading loss of underserved students, so maintained reading scores were marked as positive outcomes within the summer camp period. More than 60% of returning participants had descriptive increases in reading skills between the first and second summer camps. There were no noticeable general change patterns between the prosocial self-efficacy and reading skills. Due to the complex change patterns of students' prosocial self-efficacy across the multiple years, there were no general patterns to explain the relationship between prosocial self-efficacy and reading skills of returning participants. Through the interview analysis, I found that all interviewees had positive views on their summer learning experiences; students commented that their teacher and peers were supportive and respectful in the classroom, and the multicultural books in the camp were interesting to them. The learning and instructional contexts of Freedom Schools align with the transformative SEL approach. In this study, students' interviews aligned with the theoretical ideas of transformative SEL that using culturally relevant education may support students' positive cultural identities and successful academic achievement in racially minoritized students. The findings contribute to our understanding of students' transformative SEL experiences in Freedom Schools contexts. This approach highlights the importance of equity-based SEL implementation for underserved students. The findings of this study also shed light on the impact of Freedom Schools on students' potential learning outcomes across multiple years, from a developmental perspective. [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.]