The purpose of this study was to determine the improvement of learning quality in accounting subjects after the implementation of cooperative learning model type Student Teams Achievement Divisions (STAD) in grade XIof student IPS 2 year 2012/2013 of SMA Negeri 3 Sukoharjo. This study was an action research which implement in two cycles. The study was undertaken with collaboration between a researcher, classroom teachers, and involved student participation. The sources of data wereinformants, location of the study, events, and documents. Data was collected through observation, interviews, documentation, and test. The data was validated using both techniques and methods triangulation. Data was analyzed using qualitative data analysis which divided inti three sequential components namely data reduction, data presentation, and conclusion. The results showed that the implementation of cooperative learning type Student Teams Achievement Division (STAD) can improve the quality of student learning before the intervention to the first cycle and from cycle I to cycle II. The learning process before the intervention was teacher- centered which result in lack of student's understanding. In the first cycle, there was an increasing of student's activity and mastery of learning outcomes, although it was not optimal. The implementation of the second cycle resulted in the increasing of student's activity and mastery of learning outcome which could lead to quality learning. Based on data analysis, it can be concluded that theimplementation of cooperative learning model type Student Teams Achievement Division (STAD) can improve the quality of teaching accounting subjects for class XI IPS 2 SMA Negeri 3 Sukoharjo in 2012/2013.