The COVID-19 pandemic had significant effects on schools during the 2020-2021 school year, with many districts transitioning from traditional in-person instruction to virtual learning. The purpose of this qualitative descriptive phenomenological study was to evaluate how K-5 teachers describe their self-efficacy and how K--5 principals describe the role of transformational leadership as influencing K-5 teachers' self-efficacy in the transition to online instruction and transition back to in-person instruction during the ongoing COVID-19 epidemic, based on their lived experiences. Data were gathered using semistructured interviews with 19 participants and analyzed using thematic analysis. The themes were as follows: (a) focusing on the confidence, abilities, and skills of teachers to achieve goals; (b) building the confidence of teachers to attain educational and institutional goals; and (c) creating buy-in among teachers and stakeholders. These findings broadly aligned with the existing literature in showing how self-efficacy and transformational leadership were conceptualized by the participants. The findings also yielded both practical and research recommendations, which inform further support for transformational leadership in learning institutions and in research. [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.]