De Villiers (2007) and others have claimed that children come to understand false beliefs as they acquire linguistic constructions for representing a proposition and the speaker’s epistemic attitude toward that proposition. In the current study, English-speaking children (N=64) of 3 and 4 years of age were asked to interpret propositional attitude constructions with a first-person or a third-person subject of the propositional attitude (e.g., I think the sticker is in the red box or The cow thinks the sticker is in the red box, respectively). They were also assessed for an understanding of their own and others’ false beliefs. We found that 4-year-olds showed a better understanding of both third-person propositional attitude constructions and false belief than their younger peers. No significant developmental differences were found for first-person propositional attitude constructions. The older children also showed a better understanding of their own than of others’ false beliefs. In addition, regression analyses suggest that the older children’s comprehension of their own false belief was mainly related to their understanding of third-person propositional attitude constructions. These results indicate that we need to take a closer look at the propositional attitude constructions that are supposed to support children’s false-belief reasoning. Children may come to understand their own and others’ beliefs in different ways, and this may affect both their use and understanding of propositional attitude constructions and their performance in various types of false-belief tasks.