This paper draws on interview data to explore Australian, Canadian and Scottish teacher educators' conceptions of sustainability education (SE) within initial teacher education (ITE). Findings were generated across three themes: teacher educators' (i) conceptions of SE and SE in ITE, (ii) curriculum and pedagogical practices, and (iii) barriers, challenges and opportunities to engaging with SE. Analysis revealed inconsistency amongst teacher educators' conceptualizations of SE, and significant barriers and challenges when offering SE within ITE programs. Related opportunities highlighted destabilizing established norms within ITE programs and encouraging future thinking about the wider purposes and processes of education with preservice teachers.