In this paper we use postcolonial feminist theory to examine current physical activity guidelines for pregnant women in Canada. We argue that these guidelines marginalize pregnant First Nations women in a number of ways: a lack of cultural consideration or representation of First Nations women; recommendations and interventions that rely on Eurocentric epistemologies and biomedical discourses; the use of dominant neoliberal notions of personal responsibility for health; and physical and financial barriers to the guidelines. As physical activity is an important contributor to positive maternal health outcomes, and as First Nations women are at particular risk of excess weight gain during pregnancy, we argue that existing guidelines need to be reflective of First Nations women’s needs. Further, the creation of culturally safe physical activity resources for pregnant First Nations women may enable them to avoid excess weight gain during pregnancy and thus improve maternal health.