Sustainable development is a central concern of today's politics across the world. Different political agendas have been developed to promote sustainability and make it a political goal worldwide. As stated in Agenda 21, the political debate seems to agree that education has to play a key role in achieving sustainability. But practices focusing on Education for Sustainable Development (ESD) are rarely implemented in many educational domains, including chemistry teaching. A more thorough focus on ESD in chemistry teaching demands, among other things, a positive teacher attitude towards ESD, specific subject matter knowledge, and knowledge of suitable pedagogies. Such knowledge concerning ESD in these three areas is generally rare in the literature, particularly in the German context. This is why the current paper elaborates German student teachers' and trainee teachers understanding of sustainability and ESD, including their viewpoints on chemistry education. In this study, 87 student teachers and 97 trainee teachers answered a set of closed, Likert-type and open survey-questions that were analyzed both, qualitatively and quantitatively. The results of the study indicate that these groups show principally positive attitudes towards ESD in chemistry education. However, their knowledge is only vaguely informed in the theoretical sense. Few participants in this study possessed any clear, theory-supported concepts when it came to either sustainability, or ESD. (Contains 5 tables and 6 figures.)