Despite advances made there is still an implementation gap with regard to Education for Sustainable Development (ESD) in formal educational systems at the school level. The present paper focuses on sustainability reporting as a recently emerging practice in the school sector. It presents the approach and findings of an exploratory interview study at three pioneer schools in Germany that have started to establish sustainability reporting mechanisms. The study has examined how the reporting process is evaluated by project managers with regard to its benefits and challenges. Findings support the potential of sustainability reporting at schools to contribute to an increase in students’ participation in sustainability-related activities at school, create accountability concerning the school’s efforts, help structure the existing sustainability projects and demonstrate new possible courses of action. The high expenditure of time, the teachers’ high workload and lack of support given to the teachers have been identified as major challenges of the reporting process. Further directions for future research into reporting practices at schools are given.