This qualitative case study explored K-8 principals' perception of the contribution of job-embedded professional learning on skills and efficacy in instructional leadership, guided by Experiential Learning and Self-Efficacy Theory. The study addressed two research questions: the first explored how principals perceived the contribution of job-embedded professional learning on skills in instructional leadership, the second explored the contribution on efficacy in instructional leadership. Purposive, convenience and snowball sampling were utilized to garner 22 principals who served in the K-8 setting in three public school districts in Maricopa County, AZ. Data collection involved the Principal Self-Efficacy Scale Questionnaire (PSES) completed by 22 principals. Of the 22 principals who completed the PSES, 14 volunteered to participate in the semi-structured interviews and 8 principals from the interviews volunteered to participate in the focus groups. Thematic analysis was utilized for this qualitative case study and four themes emerged in response to research question one, job-embedded professional learning: nurtures the role of instructional leadership, focuses efforts on student success, guides the facilitation of teaching and learning, and fosters relevance and contextualization of skills. Addressing research question number two, three key themes were identified, job-embedded professional learning: validates instructional impact, fosters resilience and wellbeing, and cultivates growth mindset. Findings suggest when job-embedded professional learning is aligned to the perceived needs of K-8 principals, it significantly contributes to the acquisition of skills and efficacy in instructional leadership. [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.]