For more than three decades, considerable research effort has been expended in documenting children's development of a theory of mind (ToM), or the recognition that behavior is determined by mental states. Studies comparing ToM development in children from Western and non-Western countries have shown differences in patterns of development in various ToM tasks. Specifically, Iranian children are slower than their Australian counterparts to acknowledge that people have diverse beliefs, but at the same time they have relatively advanced understanding of how people acquire new knowledge. In the current study, our aim was to further investigate this cross-cultural pattern by evaluating 3- and 4-year-old Australian and Iranian children's belief and knowledge understanding across a range of distinct tasks designed to reflect culturally familiar situations. Results confirmed that the Iranian children were faster than the Australians in mastering tasks assessing the understanding of how and when knowledge is acquired. Iranian children, however, lag behind in passing diverse belief tasks. Scores in false belief tasks were comparable across both countries. These findings are discussed with reference to socio-cultural differences across the two countries.