In this study, the statistical thinking levels of middle school students have been examined by using M3ST statistical thinking model based on SOLO taxonomy. This model consist of 4 compenents. Definition of data, organization and reduction of data, representation of data, analyzing and interperetation of data. 90 middle school students from different classes participated in the study. In accordance with the statistical acqusitions of middle school education, open-ended and multiple choice questions have been prepared by analyzing the questions in the literature and taking opinions of professionals. Analyzing the responses of students' response, the levels of students have been searched according to the statistical thinking model. According the findings, the middle school students' levels are in the fourth level in the definition of data, it has been understood that they are in the first level in the other statistical thinking components. The students are reach higher level when reach higher class. Development and change is occur guickly particularly between 6 and 7 class. The results of the study revealed that there is a significant relationship between the grades of students and the levels of statistical thinking. Results are compared other research in this field.