This study examined how school heads managerial competencies influence teachers competence and well-being, with teachers efficacy as a mediating factor. The research focused on teachers perceptions of school leaders skills and their impact on instructional quality and job satisfaction. A descriptive research design was employed, involving 200 Del Remedio District, Division of San Pablo City teachers. Data were gathered through surveys via Google Forms and analyzed using frequency, mean, standard deviation, Pearson correlation, and mediation analysis. Results showed that teachers rated school heads managerial competencies, such as conceptual, technical, and interpersonal skills, along with organizational support and professional development, very high. Teachers efficacy and ability to adjust classroom processes and support student learning were also rated very high. Significant positive correlations were found between managerial competencies and teachers professional competence, including content mastery, pedagogical skills, classroom management, and responsiveness to learner diversity. A strong relationship was also observed with teacher well-being, job satisfaction, and commitment. Mediation analysis confirmed that teachers efficacy positively influences their competence across multiple teaching domains. These findings highlight the critical role of effective school leadership in enhancing teacher performance and well-being through improved efficacy.