Mathematical problem-solving ability is a way of thinking that can be used when trying to solve a problem, it is hoped that students can use it to solve problems in everyday life. However, the fact is that the students' mathematical problem-solving abilities are still low. One of the efforts that can improve students' mathematical problem-solving abilities is to use the Relating, Experiencing, Applying, Cooperating, transferring (REACT) mathematics learning model. REACT learning model where the REACT model is a contextual learning approach. The purpose of this study was to improve mathematical problem-solving skills using the REACT model. The research method used in this study is a Quasi-Experimental type Pretest-Posttest Control Group Design. The sample used in this study was 71 students at one high school in Jakarta. The results of this study indicate that the mathematics problem-solving abilities of students with the REACT model are better than the mathematics problem-solving abilities of students with conventional models.