This research is Classroom Action Research which aims to improve mathematics learning and students' motivation to learn mathematics in one of the MTs in Cimahi City by using a problem-based learning approach to class IX students. This research consisted of three cycles with 10 students as the subject. The research instrument used consisted of an affective assessment instrument and a cognitive test using a learning motivation attitude scale and teaching materials in the form of LKPD categorized as successful to increase student learning motivation, which was above 80%. For the mathematics learning outcomes of students in cycle 1, it shows 40% or an average value of 64, for cycle 2 it shows 60% or an average value of 71, for cycle 3 it shows 80% or an average value of 84. Meanwhile, for cycle 1, students' learning motivation shows 74 %, in the second cycle the student's learning motivation showed 78.4%, and the third cycle of the student's learning motivation showed 81.4%. So that each cycle for mathematics learning outcomes and students' learning motivation using a problem-based learning approach increases even though there are still some obstacles during the learning process.