There has been growing concern regarding youth participation in martial arts programs (Vertonghen & Theeboom, 2013). Previous studies have revealed contradictory findings of youth martial arts programs related to a potential increasing physical aggression and violent behaviors as a negative side of youth martial arts practice (Endresen & Olweus, 2005; Mutz’s, 2012; Sofia & Cruz, 2017) or producing positive youth developmental (PYD) outcomes as positive side of youth martial arts practice (van der kooi, 2020; Vertonghen & Theeboom, 2010). Little attention has been paid to the “black box” of what causes those outcomes. The black box refers to what and how martial arts are being taught to promote positive youth development (PYD). Little information is available in the literature that unpacks the black box of martial arts pedagogy. An embedded multiple case study design (Yin, 2016) was used to unpack the black box of martial arts pedagogical practices employed in three cases: 1) traditional Taekwondo program, 2) afterschool Taekwondo program, and 3) high school physical education (PE) Taekwondo program. Research participants were purposefully selected who were expected to provide-in-depth and detailed information regarding the research topic. In the traditional Taekwondo (case 1), eight (fe)male students, four parents, and two instructors participated in this study. In the afterschool Taekwondo (case 2), five (fe)male students, four parents and an instructor were selected. In the school PE Taekwondo (case 3), four (fe)male students, five program staff, and a PE teacher participated in this study. The average ages of students were 14.5 years old (case 1), 13 years old (case 2), and 15 years old (case 3). Using a mixed method approach, qualitative (interviews, focus groups, lesson reflections, and TARE post-teaching reflection) and quantitative (TARE observation, ToRQ, and PSRQ) data were collected. Qualitative data was analyzed using concept-driven and data-driven approaches to thematic analysis. A descriptive statistical analysis of quantitative raw data was conducted using measures of central tendency (i.e., mean, median, and mode). In phase one (within case analysis), each case was examined in-depth with the qualitative analysis to unpack the black box of martial arts pedagogy and positive youth developmental experiences. In phase two, (cross-case analysis), a pattern-matching and explanation building was carried out to identify the contrasts and similarities through comparing between the cases. Both the quantitative analysis (descriptive statistics) and the qualitative analysis were used for the comparison. Based on the procedures, findings revealed that the particularities of martial arts pedagogy were related to cultural heritage and promoting explicit life skills education in case 1; adaptive Taekwondo teaching, promoting transfer of Taekwondo life skills in case 2; and integrating restorative practices with Taekwondo teaching in case 3. The teaching strategies that characterized their instruction were directed teaching for case 1, promoting peer teaching for case 2, and facilitating collaborative learning for case 3. Results also showed that PYD experiences were characterized differently among the cases that were a) youth taekwondoists’ journey to the black belt that involves systematic goal setting and accomplishment as well as mind-body practices, b) disciplined kids who care about others and their personal life by actively applying the life skills to daily life, and c) recognizing individuals that promotes self-expression in students and positive social interaction. On the other hand, common positive youth developmental outcomes consistently identified across the three cases included a) positive identity (e.g., self-efficacy and sense of belonging), b) cultural competence (e.g., awareness about different cultures), and c) contribution (e.g., personal and community development). Throughout the investigation, it was confirmed that martial arts have potential as a vehicle to promote positive youth developmental outcomes, such as life skills, character development, and social-emotional learning. Martial arts curriculum can be flexible to adapt needs of teachers and students (e.g., afterschool program and physical education). To conclude, more research needs to 1) pay attention to the potential of the martial arts-based youth development programs, 2) identify the positive youth developmental outcomes, and 3) explore the pedagogical processes that foster such outcomes