The background of this research is the low learning outcomes of mathematics in class VIII.1 SMPN 1 Sawahlunto. The purpose of this study was to determine the increase in mathematics learning outcomes through the cooperative learning model Type Numbered Heads Together in class VIII.1 students totaling 30 people, consisting of 15 girls and 15 boys. This type of research is a classroom action research conducted in class VIII.1 SMPN 1 Sawahlunto. The technique used in data analysis is a test. The research was carried out in two cycles. Each cycle consists of planning, implementing, observing and reflecting. The results showed that the application of the numbered heads together learning model could improve student learning outcomes. In the first cycle, obtained an average of 72.00 learning outcomes, while in the second cycle, the average obtained is 79.33. Classical completeness in the first cycle is 50%, while in the second cycle the classical completeness is 80%

Keywords : Learning Outcomes, Learning Models, Numbered Heads Together