Purpose: The purpose of this phenomenological study was to identify and describe the best practices school counselors from exemplary alternative education schools in San Bernardino County use to support social emotional learning (SEL) using the Collaborative for Academic, Social, and Emotional Learning (CASEL) core competencies (self-management, self-awareness, social awareness, relationship skills, and responsible decision-making). An additional purpose of the study was to describe the CASEL SEL core competencies that were perceived as most important by school counselors from exemplary alternative education schools in San Bernardino County. Methodology: This qualitative phenomenological study identified and described the best practices school counselors from exemplary alternative education schools in San Bernardino County implement to support SEL using the CASEL core competencies. The researcher created in-depth, semistructured interviews that were composed of 15 interview questions consistent with the research questions. Findings: Examination of phenomenological data revealed 20 themes, which led to 7 key findings and 2 unexpected findings. The following were the key findings: (1) School counselors assist students with strategies in identifying stress and various stress management strategies. (2) School counselors identify practices that help students to understand their emotions. (3) School counselors ensure that students practice empathy to relate to themselves, peers, and others. (4) School counselors work to educate students in all forms of communication. (5) School counselors educate students to think critically. (6) School counselors demonstrate that communication and establishing relationships are a fundamental part of SEL. (7) Communicating and building rapport are skills needed to build relationships. Conclusions: This study concluded that school counselors who support SEL using the CASEL core competencies perceive that communication and building rapport are the best practices when implementing SEL. The most important CASEL core competency practice to reach students is establishing and maintaining relationships. Recommendations: Further research is recommended to study the perspectives of students in alternative education and SEL. [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.]