Abstract: The purpose of this study is to improve the performance of teachers at SD Negeri 1 Tanjungori Tambak District in learning in class. This research was conducted at SD Negeri 1 Tanjungori, Tambak Subdistrict in the second semester of 2017/2018, with a total of 6 classroom teachers in the elementary school. The method used in this study is the School Action Research (PTS) method, while the actions taken in this research activity are the application of collaborative educational supervision in every learning in the classroom. This research was conducted in two cycles. The stages of the action carried out in each cycle are 4 stages, namely: (1) action planning; (2) implementing actions; (3) observations / observations; (4) reflection. The results showed that through the implementation of collaborative educational supervision periodically can improve the performance of teachers at SD Negeri 1 Tanjungori Tambak District in learning in the classroom. The implementation of collaborative educational supervision periodically can improve teacher performance in implementing learning and in assessing student achievement.Keywords: collaborative educational supervision, teacher performance, classroom learning