There are gender differences in educational attainment amongst British children and there is evidence that these differences emerge early in life. In this study we investigate whether boys' and girls' early educational attainment levels are similarly related to disadvantage in the family environment. This study uses survey data from the Millennium Cohort Study linked with the teachers Foundation Stage Profile assessment for children in the primary year of school in England between 2005 and 2006. The study finds lower attainment in communication, language and literacy and mathematical development for both boys and girls in families experiencing socio-economic disadvantage. Early motherhood, low maternal qualifications, low family income and unemployment most strongly predict lower scores. Tests for gender interaction shows boys in families where mothers are young, where they lack qualifications or if they are living in poor quality areas are more disadvantaged compared to girls in similar circumstances. (Contains 1 table, 2 figures and 4 notes.)