Current theory and research support the conclusion that gender and the interdependent construct of sex are not binary phenomena. Yet, how well do the measurement practices of Canadian psychologists align with this consensus? Although there are many ways to address this critical question, we take three approaches: (a) to understand cultural norms, we survey the gender/sex options available for national and provincial government identification across Canada; (b) to understand researcher practices, we review the gender/sex demographic measures used in empirical articles published in 2020 in three Canadian Psychological Association journals; and (c) to understand the guidance researchers receive, we review the websites of research ethics boards at Canadian universities. Our results reveal that while most Canadian identification allows individuals to self-identify into three gender/sex categories (female, male, X), the vast majority of the psychological research that we surveyed relied on binary gender/sex classification and very few research ethics board websites offered publicly available guidance that could help correct such errors. These common exclusionary measurement practices are disconnected from Canadian norms and violate the ethical principles of our field. Binary measures exclude people whose identities fall beyond the gender/sex binary, reinforce a colonized conception of gender/sex that is inconsistent with the ideals of reconciliation with the Indigenous Peoples of Canada, and convey an outdated and discriminatory attitude to all participants who complete psychological surveys. We recommend simple practices to resolve these ethical concerns, allowing researchers and administrators to take concrete steps towards respecting gender/sex diversity in Canada. Public Significance Statement Canada formally recognizes and protects diverse gender identities. Yet, the majority of Canadian psychological research we surveyed use exclusionary, binary gender/sex measures, a practice that violates Canadian values, including efforts towards reconciliation with the Indigenous Peoples of Canada. Canadian research ethics boards rarely provide publicly accessible recommendations for inclusive gender/sex measurement despite such practices aligning with the ethical codes that govern psychological science.
