The purposes of this research were to: 1) determine the strategic leadership of school administrators in the 4.0 era in the education sandbox in Rayong Province, 2) determine the effectiveness of these schools, 3) determine the relationship between the strategic leadership of school administrators in the 4.0 era and the effectiveness of these schools, and 4) determine the strategic leadership of school administrators in the 4.0 era affecting the effectiveness of these schools. It was quantitative research. The research sample was a group of 265 teachers from the secondary schools in the education sandbox in Rayong Province in the academic year 2022. The sample size was determined by using Krejcie and Morgan’s table, and proportional stratified random sampling was used based on the size of schools. The research instrument was a five-rating scale questionnaire divided into 2 parts: part 1 was a questionnaire about the strategic leadership of the administrators with a reliability of 0.98, and part 2 was a questionnaire about the
effectiveness of the schools with a reliability of 0.97. The statistics used for data analysis were:
mean, standard deviation, the Pearson’s product moment correlation coefficient, and multiple
regression analysis.