Schools administration is a working process that has the school administrators systematically perform the tasks in the schools. The school administrators have authority and responsibility to make a decision that affects the school effectiveness. The objectives of this research were to : 1) study level of school administration, 2) study the effectiveness level of the schools, 3) study the relationship between school administration and school effectiveness and 4”) create a prediction equation of school administration that affected the school effectiveness. The sample was a group of 373 teachers in the schools under Chanthaburi Primary Educational Service Area Office 1 and 2. The sample size was calculated using Krejcie and Morgan’s table and stratified random sampling method by using Education Service Area as a random class. The research instrument was a five-level rating scale questionnaire with a reliability of 0.97. The statistics used for data analysis were: percentage, mean, standard deviation, Pearson product-moment correlation coefficient and sample regression analysis.
