This paper analyzes the effects of different aspects of family background such as family income, parental education, parental job, family size, and the socioeconomic status of parents on educational performance of higher education applicants in Iran. The gathered data from the Iranian university and college applications in 2010 is analyzed using data mining methods to investigate the effects of family background variables on entrance examination grades. The results of this analysis show that parental education, parental job, and the socioeconomic status of family have large effects on entrance examination grades, and as a result on university and college acceptance and also on educational performances. Results of this study provide a better understanding of the factors that could have significant impact on the applicant's admission, and as a result on the higher education achievement in Iran. Such insights can assist responsible people to make good decision about the relative advantages and limitations for higher education attainment.