Context knowledge generally plays an important role for learning statistics, but insights are needed into its role for the development of statistical literacy. This study reports on a design research project in which a digital learning environment was developed to foster middle school students’ critical statistical literacy. Design principles include a focus on building context knowledge and scaffolding reflections of statistical arguments. The qualitative analysis shows that students use context knowledge to reflect on limitations, relevance, and consequences of statistical arguments. It also reveals that this context knowledge is often taken from phenomena which are outside the current learning environment in a subjective and metaphorical use of context.