This study reports on the kind of school leadership style that best suits for promoting teachers' job satisfaction in primary schools in Tanzania. The study employed cross sectional research design with samples of 200 teachers from 20 selected primary schools in Songea and Morogoro districts. Interviews, documentary analysis and questionnaires were used to collect data. The data were analyzed both qualitatively and quantitatively using tables, frequencies and percentages. It was found that the democratic leadership style was the most dominant in best performing primary schools. It is therefore suggested that there is much to be learnt with democratic leadership style as a copying strategy in least performing primary schools. Moreover, level of teachers' job satisfaction was reportedly high in best performing schools compared to least performing schools. The findings commended that democratic leadership style is the one which promotes high teachers' job satisfaction among teachers in primary schools.