Background: A growing body of research shows that the beliefs we hold about the nature of knowing and knowledge (epistemic beliefs) may mediate moral reasoning. However, a limitation of much of the research in the area of epistemic beliefs is the lack of a longitudinal approach. Aims: The study investigated longitudinal changes in Australian elementary school children's beliefs about knowing and knowledge (epistemic beliefs) across three judgement domains (personal taste, ambiguous facts, and moral values). Sample: The participants in this longitudinal study were tracked from Year 1 through to Year 3 of primary school. In Year 1, there were 169 participants (83 boys, 86 girls) aged 6-7 years (M = 6.7, SD = 0.32). In Year 2, there were 156 participants (79 boys, 77 girls), and in Year 3, there were 129 participants (65 boys, 64 girls). Methods: Using vignettes that reflected each of the three judgement domains, children were interviewed about the beliefs held by two puppet characters. The interviews took place each year across the early years of elementary education in Year 1, Year 2, and Year 3. Results: Findings revealed that children's epistemic beliefs in each of the judgement domains became more subjectivist over time but that the age at which this occurred differed according to the judgement domain in question. Conclusions: We argue that it is important for teachers to pay attention to children's beliefs about the nature of knowledge and knowing in the process of scaffolding their reasoning about moral values for active citizenship.