This document discusses several theoretical models of identity development for gay, lesbian, bisexual, and transgender (GLBT) students. It describes Cass's 6-stage model of homosexuality identity formation from 1979 and D'Augelli's 6-interactive process model from 1994. Cass's stages include confusion, comparison, tolerance, identity acceptance, identity pride, and identity synthesis. D'Augelli's processes are exiting heterosexual identity, developing a personal GLBT identity, developing a social identity, becoming a GLBT offspring, developing GLBT intimacy, and entering a GLBT community. The document also addresses stages of bisexual identity development and notes a need for more validation of theories and research on differences between gay men and women.