This research incorporated an ecological approach to examine American and Northern Irish children's understanding of the 2003 war in Iraq and the sources of information from which they acquired that understanding. Responses to interviews indicated that the children from the two countries had some common conceptions of and sources of information about the war. However, American and Northern Irish children also differed on several items, suggesting that the macrosystem (e.g. sociopolitical context) plays an important role in children's conceptions of the war. Additionally, the exosystem (media) also played an integral role, as did the microsystem (parents), although to a lesser extent. (Contains 1 table.)