Gender often influences whether or not children attend or remain in school. Across the world, girls are more likely than boys to be out of school, and the poorest girls/women from the most disadvantaged rural areas tend to have the lowest educational attainment levels. The reasons why girls are more likely than boys to be out of school relate to social power structures and socially-constructed norms that define the roles that boys/men and girls/women should play. These gender roles affect their rights, responsibilities, opportunities and capabilities, including their access to and treatment in school. While educational exclusion based on gender disproportionately affects girls/women, it also affects boys/men. This brief provides an overview of the relationship between gender and educational attainment and suggests ways of mainstreaming gender to improve school access and retention.