This research is classroom action research (PTK), which aims to improve learning outcomes and interest in learning mathematics for class VIIIB students at Belibis Catholic Middle School, Makassar. The subjects in this study were 21 class VIIIB students of Belibis Catholic Middle School, Makassar. The data collection techniques used in this research were student mathematics learning outcomes tests, student activity observation sheets, teacher activity observation sheets and student interest questionnaires for each cycle. Data analysis techniques used in this study are qualitative and quantitative. The results of this research show that after being given action using the Team Games Tournament (TGT) type cooperative learning model, there was an increase in the average score of students' mathematics learning outcomes tests for opportunity material at the end of cycle I which was obtained at 71.05 from the ideal score of 100 and at the end of the cycle II increased to 82.81 from the ideal score of 100 with the mastery of students' understanding of mathematics learning outcomes increased by 33.33%. The standard deviation at the end of cycle I was 9.584 and the standard deviation at the end of cycle II was 7.332, based on the assessment categories used to obtain student mathematics learning outcomes scores which were categorized as complete in cycle II, there were 1 student to 20 students in cycle II. The interest in learning mathematics of class VIIIB students at Belibis Catholic Middle School, Makassar, through the Team Games Tournament (TGT) type cooperative model, obtained a score in cycle I of 73.49% while in cycle II it was 83.57%. The increase in the two cycles can be said that students' interest in learning reaches the existing categories. From the results of this research, it can be concluded that by implementing the Team Games Tournament (TGT) type cooperative learning model consisting of cycles I and II, there is an increase in the quality of learning, namely increasing learning outcomes and interest in learning mathematics for class VIIIB students at Belibis Catholic Middle School, Makassar.