Federal data show that many girls are struggling across almost all measures of well-being--including substance use, experiences of violence, mental health, and suicidal thoughts and behaviors. Girls' well-being can be affected by their experiences in public schools, and the detrimental effects of removing students from the classroom for discipline (exclusionary discipline). The Government Accountability Office (GAO) was asked to review the effect of disciplinary policies and practices on girls in U.S. public schools. This report (1) examines what national data show about discipline disparities among girls in K-12 schools across various student characteristics, including race and disability, and school characteristics; (2) identifies factors that contribute to differences in discipline among girls in school; and (3) describes girls' perceptions of safety and belonging in school. To understand discipline patterns for girls, GAO conducted descriptive and regression analyses using 2017-18 Education civil rights data (2020-21 data was anomalous because in-school attendance was affected by COVID-19) and a dataset that captures student infractions and associated disciplinary actions. To identify factors contributing to differences in discipline among girls, GAO reviewed empirical research and interviewed stakeholders specializing in the discipline and experiences of girls in schools. To examine girls' perceptions of safety and belonging in school, GAO analyzed nationally representative survey data from the 2017, 2019 and 2022 National Crime Victimization Surveys, School Crime Supplement.