The aim of this study is to examine the long-term cognitive effects and educational outcomes of being born small-for-gestational-age (SGA). It also assesses whether the family’s attitude towards education modifies the effect of SGA on cognitive performance. A total of 9598 children born in 1953 and living in the Stockholm metropolitan area in 1963 were included in this study. Data were obtained from the Stockholm Birth Cohort. Multiple ordinary least square regressions analyses suggest that SGA children have lower mean verbal, spatial and numerical test scores than appropriate-for-gestational-age (AGA) children. However, these differences are small. Other results from modification analyses indicate that the effect of SGA status on cognitive performance is modified by the family’s attitude towards education. Additional logistic regression analyses suggest that the unadjusted difference in log odds of attaining higher education is largely explained by the family’s attitude towards education. The results suggest that the detrimental influences of being born SGA on some cognitive and educational outcomes are limited and may be reduced.