Mathematical self-efficacy and student achievement are of particular concern to aspiring teachers in the 21st century. The purpose of this study was to examine the relationship between mathematics self-efficacy and student academic achievement in prospective elementary school teachers. This research is a correlation study. The research sample consisted of 40 students schools for the 2018 academic year were selected by purposive sampling. Measurement mathematics self efficacy uses the MSE scale adapted from May Diana, meanwhile measurement of student achievement using test scores. Data analysis using product moment correlation. The results showed that students' mathematics self-efficacy has a relationship with student academic achievement in Mathematics courses. The higher the mathematics self efficacy, the higher the achievement them, on the contrary, the lower the mathematics self efficacy, the lower it is student academic achievement in the Mathematics course.