The Gay, Lesbian and Straight Education Network (GLSEN) is the leading national education organization focused on ensuring safe schools for all students. GLSEN envisions a world in which every child learns to respect and accept all people, regardless of sexual orientation or gender identity/expression. This entry explores GLSEN's history and major contributions to diversity issues in K–12 education.

GLSEN works to educate teachers, students, and the public at large about the damaging effects homophobia and heterosexism may have on healthy school climates and on youth and adults alike. Furthermore, GLSEN recognizes that other forms of oppression such as racism and sexism have similarly adverse impacts on communities and supports schools in seeking to redress all such inequities.