In this study, the relationship between TEOG mathematics achievement and social economic status (SES) was examined. In the research, student's 2013 first semester TEOG mathematics achievement was used as dependent variable and SES is used as independent variable. In the context of the research, SES of students and math achievement scores were used as a first level, the average SES of school-level variable is used as the second level in hierarchic linear model (HLM). In the research, 32 secondary schools, which are located in Altindag district within the boundaries of Ankara, and 1194 students participated. SES and 2013 TEOG student mathematics achievement of the test scores were used. The difference between average mathematics achievements of the schools was found as statistically significant. It is determined that the effect of mean SES of the schools on mathematics achievement was not statistically significant.