This article reports on an investigation of student teachers’ learning about education for sustainable development (ESD). Phenomenographic data were collected using open proformas and interviews from student geography teachers taking the University of Oxford Post-Graduate Certificate in Education (PGCE) in 2003–2004. The data analysis focuses on what the cohort of student teachers perceived as their learning about ESD and the sources that contribute to it. Extracts from the data illustrate their conceptions of subject matter, regarding the relevance of sustainable development for school students, its complex and contested meanings, and the challenges it presents for learning and learners. Data on conceptions of pedagogy illustrate their depth of learning about the relationship between ESD subject matter and approaches and strategies in teaching and learning, and features of pedagogy that illustrate interactive teaching strategies. Various school and university-based sources were identified by the student teachers as leading to specific aspects of learning about ESD, although many of the accounts illustrate a combination of sources. Implications of the findings for teacher education and research in ESD are also discussed.