This study explored the instructional competencies, leadership practices, and challenges faced by Master Teachers in the Division of Tayabas City, Quezon, and Lucena City during the school year 2025–2026. It aimed to determine the level of instructional competencies and leadership practices and examine their relationship with professional development engagement. A descriptive-correlational research design was employed, using a survey questionnaire as the primary data-gathering instrument among selected Master Teachers. The findings revealed that Master Teachers demonstrated a highly competent level of instructional practices, particularly in classroom management, pedagogical knowledge, and assessment techniques. They also exhibited strong leadership practices in terms of collaboration, communication, and adaptability. However, they experienced significant challenges in terms of workload, indicating the need for institutional support to reduce task overload. Further results showed that instructional competencies and leadership practices were positively correlated, with leadership practices fully mediating the relationship between instructional competencies and professional development engagement. Overall, the study highlighted that strong leadership practices enhanced the impact of instructional competencies on professional growth, underscoring the importance of supportive leadership systems in promoting continuous teacher development and school improvement.