This study examined the relationship between professional development, work ethics, and job performance among teachers in public central schools in Davao City. Utilizing a descriptive quantitative research design with mediation analysis, data were collected from 300 teachers through adapted questionnaires using cluster sampling technique. The findings revealed that teachers exhibited very high levels of professional development (M = 4.30), work ethics (M = 4.57), and job performance (M = 4.31). A significant positive correlation was found between professional development and job performance (r = 0.58, p < 0.001), as well as between work ethics and job performance (r = 0.65, p < 0.001). Mediation analysis confirmed that work ethics partially mediate the relationship between professional development and job performance. The study underscores the importance of structured professional development programs, ethical reinforcement training, and collaborative learning environments in strengthening teacher effectiveness and promoting quality, equitable education aligned with Sustainable Development Goal 4.