This study highlights the mediating effects of organizational climate to professional standards of school heads and organizational efficacy. School heads, as a bailiff of school, play a vital role in fostering an environment conducive to effective teaching and learning. Assessing professional standards of school heads is significant to teachers effectiveness and substantial in promoting good organizational climate. The study employed a descriptive-correlational design and mediating analysis. Also, it utilized survey questionnaires to determine the assessment of the respondents to professional standards of school heads, organizational climate and organizational efficacy. The findings suggest that professional standards of school heads significantly affect the organizational climate. Likewise, organizational efficacy significantly affected by the school heads professional standards. Moreover, the data gathered stated that organizational climate have significantly mediating between professional standards of school heads and organizational climate.  Thus, evaluation and reflection on professional standards of school heads are necessary for further development and improvement of leadership skills and be able to nurtures teachers effectiveness and school climate.     Keywords: Professional Standards of school heads organizational efficacy organizational climate