This paper investigates the effects of gender and family background on educational attainment in South Korea during the 1950s-1990s. In particular it focuses on the interplay between gender and family backgrounds in educational attainment. Previous studies tend to assume a uniform gender gap in different family backgrounds without precise analysis. Conventionally, family background inequality and gender inequality in educational attainment are regarded as the results of different social mechanisms. However, it is possible to observe that gender gaps may vary between family backgrounds. Using the 1998 Korea Labor and Income Panel Survey data (KLIPS) this study shows that varied gender gaps exist between different family backgrounds among respondents born in 1943-1972, e.g., the gap is greater for the farming class family. On the other hand, a cohort analysis reveals that the interplay between gender and family backgrounds is different between birth cohorts. There is a uniform gender gap among those born in 1943-1952, 1953-1962 and 1963-1972. Of note, however, respondents from service class origins in the 1963-1972 cohort show no gender gap in educational attainment. The two analyses indicate that the gender inequality is closely associated with family backgrounds. Hence, this study concludes that women’s educational opportunities are affected not only in terms of gendered cultures, but also in terms of family’s socio-economic situations in the 1950s-1990s.