This study aimed to analyze principals' managerial competency. The respondents of the study comprised of 11 principals and 110 teachers in the Laboratory High Schools (LHSs) of State Universities and Colleges (SUCs) in Region III, Philippines. The study used the Competency Framework for Southeast Asian School Heads, 2014 Edition formulated by the Southeast Asian Ministers of Education Organization Regional Center for Educational Innovation and Technology (SEAMEO INNOTECH) to measure the competency of school managers/administrators on aspects such as (1) Strategic Thinking and Innovation, (2) Instructional Leadership, (3) Personal Excellence, (4) Stakeholder Engagement, and (5) Managerial Leadership. The results showed that the laboratory high school principals always exhibit competencies primarily on leadership in instruction, personal improvement and excellence and engagement with the community. However, the study found that there was a need for principals to improve in strategic thinking and innovation and managerial leadership competency aspects. The study found a no significant difference on the perceived attributes of managerial competency when the respondents are grouped according to sex. Moreover, the analysis of variance result established a difference on the perceived principals' personal excellence and managerial leadership competencies when grouped according to respondents' highest educational attainment. The study suggested that the State Universities and Colleges in Region III may design and pursue activities that can help improve the strategic thinking and innovation and managerial leadership competency aspects of principals aimed to adequately address the growing expectations and demands of the students and other stakeholders of the laboratory high schools.