It is little wonder that there is national consensus on the necessity for school physical education to facilitate holistic development of all learners. Moreover, given the increased mental health issues that K-12 students are facing, it is important to consider a strengths-based approach to physical education that focuses on the holistic development. Positive youth development (PYD) is such a strengths-based approach but there is limited evidence of its utility in K-12 physical education. PYD aligns with the adventure-based learning (ABL) pedagogical model in physical education, which focuses on developing the personal and social skills of students. Thus, the purpose of this qualitative study was to explore the use of a virtual professional development workshop on teachers' knowledge and understanding of ABL and PYD and their perception of using ABL to foster PYD. A qualitative case study design was adopted as a methodological approach. Five in-service physical education teachers were selected as key informants. Data were gathered through individual interviews, focus group interview, videotaping and field notes, researcher's memos, and participants' written journals. Data were analyzed using inductive analysis. The findings of this study indicated that the virtual professional development workshop was helpful in supporting teachers' learning and understanding of ABL and PYD, and their perception of using ABL to foster PYD. Specifically, the teachers understood ABL as a useful strategy, particularly as a good starter of a new academic year. They also perceived that, using the ABL model, it was feasible to foster PYD within physical education settings. Given the teachers' learning about ABL and PYD, it was determined that the content of the virtual professional development workshop was effectively delivered to the teachers. Four specific factors were highlighted as important for the effectiveness of the workshop: (a) uniqueness of the professional development activities, (b) providing useful resources ahead of time, (c) hands-on experience, and (d) alignment with teachers' philosophy of teaching. Based on their learning in the virtual professional development workshop, the participants perceived that teaching ABL to foster PYD in their physical education program was possible. At the same time, they felt that they needed to modify the ABL lessons to their specific teaching context. The participants also perceived that the ABL activities would be beneficial to their students' social and emotional competencies, interpersonal development, and sense of enjoyment of physical education. Based on the findings, I provided implications for in-service teacher professional development, K-12 physical education, and physical education teacher education programs. Then, recommendations for future research were given along with the limitations of the current study. [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.]