This booklet is about the combined effects of gender and social exclusion on student participation and performance in basic education. How extensive is the problem? Why is it important? What education policies act as hidden barriers? Are legal and administrative remedies sufficient? What about affirmative action? Which policies have been effective in reaching and teaching socially excluded girls, and which ones have not? Are some remedies better suited to some countries than to other countries? What is affordable for developing countries? This booklet addresses these questions in order to help countries to: adopt education policies and practices targeted at girls from socially excluded groups, meet their Millennium Development Goals for Education, and achieve the social and economic benefits of girls’ education.