Abstract The strategic leadership is an ideal type of administrative personnel. The schools under the Municipality are the function of decentralization in Thailand which was just recently implemented. The objectives of this study were to study: 1) the level/s of strategic leadership 2) the level/s of effectiveness in the school and 3) the relationship between strategic leadership performance on school effectiveness. The samples consisted of 32 school leaders and 217 teachers from 11 schools under the municipality of Khon Kaen. The research instrument was a set of five-rating scale questionnaire. Descriptive data analysis were employed using SPSS. The Multiple Correlation Analysis and a test for multi- collinearlity correlation analysis of independent variables were also utilized. The results indicated that the level of strategic leadership was ranked at a high level. When considering at different functions, the mean scores showed from high to low level as: strategic implementation, monitoring and evaluation, organization culture, and the specification of strategy respectively. The level of school effectiveness also ranked at a high level with mean scores in each aspect from high to low as: students’ characteristics, satisfaction of teachers’ performance, school change and development, school climate and environment, and students’ achievement respectively. Regarding the relationship between strategic leadership and school effectiveness, there was a positive correlation at a medium level with statistically significant difference at 0.01 level and the multiple regression indicated r=0.721 with the prediction power 52.0 percent ( r=0.520).