Educating students about global citizenship remains a critical challenge for educators, particularly in Australia. Introducing and navigating curricula content considered too “sensitive” or “controversial” for open classroom discussions is part of this critical pedagogic challenge. We argue for the enactment of a critical pedagogy for Global Citizenship Education (GCE) through the Humanities and Social Sciences (HASS) curriculum in a primary school serving a culturally and linguistically diverse, disadvantaged community in Australia. We draw on three key concepts developed by Gayatri Chakraborty Spivak—sanctioned ignorance, subaltern, and marginality to explore challenges around GCE practices. We suggest that in selecting topics for discussion teachers may attempt to protect students from troubling experiences of perceived and real past traumas. This may unintentionally close down classroom discussions, silence some student voices and limit the production of classroom knowledge. Data generation involved a series of reflective conversations between two teacher-researchers. We conclude by discussing the implications of understanding the relation between theory and practice for teacher education, and current policy initiatives which define classroom readiness in narrow, restrictive ways. We propose that initial teacher education courses need to ensure that pre-service teachers grapple with the complex ideas proposed by postcolonial scholars in developing socially critical pedagogies for GCE.