Decreasing phenomena in teacher performances could be seen from number of teacher who didn't do their job properly, taught without showing a good role model. The purpose of this research is to see the significant influent of teacher's professionalism, work climate, and leadership's style from school principal to teachers performances at public Middle School at Sukawati regency. This research used Ex Post Facto method correlation. Sampling was taken from all middle school at Sukawati regency which is 176 samples. Due to the USAge of Proporsional Stratified Random Sampling into this research, the number of sample that been used during research become 123. The result showed that professionalism gave positive and significant influence 45,6% toward performances, 48,7 % toward work climate, 46,3% toward principal leadership style, and 67,4% all together. Based on this research, it can be concluded that there were positive and significant influences from professionalism, work climate, and leadership style to the teacher's performances at Sukawati regency separately or continuously.