This research aimed to describe mathematical representation abilities and self-concept of students in SMP Negeri 1 Kalibagor. It was a qualitative descriptive research. The subject of this research was students in class VIII A SMP Negeri 1 Kalibagor. Subjects were selected by purposive sampling consisted of three students as respondents for each learning achievement. Test, questionnaire, interview and documentation were used as data collecting technique. The research finding on students indicated that: 1) students with high achievement had positive self-concept, so that students were able to represent data or information into diagrams; to solve problems involving mathematic symbols; and involve written text in problem solving. 2) Student group with medium achievement had positive self-concept so that students were able to represent data or information into diagrams; to solve problems involving mathematic symbols. 3) Student group with low achievement had negative self-concept so that students were only able to represent data or information into diagrams.