This research aimed to describe students' mathematical abstraction ability at SMP Negeri 4 Purwokerto viewed from their learning achievement. This was a descriptive qualitative research and the data obtained were analyzed using Miles and Huberman model which included data reduction, data presentation, and conclusion drawing. The subjects in this research were students of grade IX H. The students were grouped into three groups based on their achievement: high, moderate, and low achievement group. Three respondents were selected from each group using purposive sampling technique. The data were collected using tests, interviews, and documentation. Based on the results of the research, it can be concluded that: (1) Students with high learning achievement were able to identify objects through direct observation, to identify the characteristics of objects manipulated or imagined, to present mathematical ideas in language and mathematical symbols, and to apply mathematical concepts to the appropriate context. (2) Students with moderate learning achievement were able to present mathematical ideas in language ​​and mathematical symbols and to apply them to the appropriate context.
(3) Students with low learning achievement were able to present mathematical ideas in language and mathematical symbols.