Sexism is gender-based prejudice or discrimination. As with other forms of prejudice and discrimination, it functions to maintain status and power differences between groups in society. One manifestation of sexism involves prejudice and discrimination against girls and women who seek to achieve in prestigious fields traditionally associated with males. Another manifestation of sexism, however, occurs when pressures are placed on boys and men to conform to traditional conceptions of masculinity. Over the last two decades, an increasing number of developmental and educational psychologists have become concerned about sexism directed toward children and adolescents in school contexts. Our chapter reviews the research on this topic. After providing an overview of different processes related to sexism, we examine how it is manifested in school contexts. Sexism is seen through gender-stereotyped biases against girls and boys in academic and athletic achievement. Also, it occurs through sexual harassment in social interactions. We also address factors related to children's awareness of sexism and coping responses to sexism. Finally, we consider possible ways to reduce sexism and foster effective coping in schools.