Despite the positive outcomes associated with social-emotional Learning (SEL) programs, there is a need to address social and emotional competencies (SEC) development for international school leaders, which is crucial for nurturing healthy school climates and fostering positive social-emotional outcomes. The purpose of this study was to explore international school leaders' perceptions of their experience with their own SEC development and how SEC has supported SEL implementation in their respective schools. Mahfouz et al.'s (2019) prosocial leadership model served as the conceptual framework, which highlights the pivotal role of school leaders SEC in fostering successful social-emotional and academic outcomes within their school community. A qualitative descriptive case study design was used to explore the perceptions of 11 participants from international schools with a regular membership in the Tri-Association regions in Colombia, the Caribbean, Central America, and Mexico. Data collection methods included 11 virtual semistructured interviews, one synchronous focus group session, three asynchronous focus group sessions, and document analyses. Thematic analysis identified six key themes: (1) acknowledging the role in leaders' lives, (2) enhancing preparedness as leaders, (3) incorporating networking and external support, (4) influencing SEL initiatives, (5) highlighting challenges in SEL initiatives, and (6) prioritizing SEL initiatives through collaboration. The findings revealed that international school leaders recognized the importance of SEC development and the connection between well-being and successful SEL implementations. They emphasized the need for formal and informal PD opportunities incorporating networking and external support. The implications suggest tailoring leadership training programs to incorporate SEC development, integrating networking opportunities for mutual learning, embracing collaborative practices, and prioritizing the leader and staff's SEC development before focusing on students. [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.]