Implementing social-emotional learning (SEL) at K-12 online schools is critical for the growth of students. The purpose of the basic qualitative study was to explore the perceptions of online K-12 teachers to understand the leadership support needed for teachers who are implementing SEL curricula under transformational leadership and whole-child frameworks. Limited research has addressed the impact of school leadership and the implementation of SEL in an online environment. Purposeful sampling was used to locate 15 K-12 online teachers in the United States as participants for the basic qualitative study. Participants were asked to respond to a questionnaire and questions about the school's SEL implementation practices and support for implementation practices by leadership. A follow-up five-member focus group was conducted to gather more insight into the results from the questionnaire. The experience of leadership support with SEL and the impact of a principal's leadership style on SEL implementation was examined. Data was collected and analyzed manually for thematic patterns. Leadership, communication, professional development and training, and success emerged as the themes from the data. The themes indicated a need for teacher support in SEL implementation through communication and professional development and training. School leaders should have a transformational leadership style to implement SEL effectively in online classrooms. [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/en-US/products/dissertations/individuals.shtml.]