In 2002, jurisdictions across Canada began adding two new protected grounds to their human rights laws: gender identity and/or gender expression. Gender identity protections generally apply only to transgender people, whereas gender expression protections "may apply" to all Canadians in places like K-12 schools. However, it remains legally unclear what kind of action, utterance, or pattern constitutes gender expression discrimination, and who can access related protections. In search of clarification, this article explores how the meaning of gender expression is being constructed within policy documents (N = 206) authored at the level of Ontario's English public secular school boards.