Determining the depth of discrimination against gender and sexual minority groups in Catholic schools of selected western nations is best undertaken from an international-comparative perspective. In this article, we compare the Canadian case of Alberta's 'washroom wars' and a 'gender row' over uniform changes in an Australian Catholic high school. In each case, practises inclusive of gender diversity in Catholic schools were framed as a departure from Catholic doctrine. To explore how oppressive structures exist and operate within schools, we examine media accounts of each case using Critical Discourse Analysis and contextualize this analysis by examining Canadian and Australian educational and legal settings. We find that despite differing legal frameworks, some Catholic schools continue to place Canonical law above the rights of transgender and gender-diverse students in both countries. We therefore argue that it is the Catholic system's institutional stance on gender and sexual diversity that perpetuates discrimination.