Previous research involving Hong Kong Chinese parents and their children showed that parental home involvement, beliefs of their children’s cognitive ability and their expectations for academic achievement mediated the relationship between their children’s cognitive ability and school achievement scores. This mediation effect was interpreted as the cognitive-affect model of academic achievement. The current research confirms the generalizability of the findings and tests the hypothesis that there are cultural differences in the mediation effects with the inclusion of non-Chinese students and their parents as a comparison group. The responses from 103 Chinese speaking (CS) and 163 non-Chinese speaking (NCS) primary students and parents from two schools in Hong Kong were analyzed using structural equation modeling. Student measures included self-concept, cognitive ability and academic achievement in mathematics, English and Chinese. Parent measures included home involvement, beliefs of their child’s cognitive ability and expectations of academic success. Initial model showed that parental expectations mediate the link between cognitive ability and academic achievement for both CS and NCS groups, with parental involvement predicting English achievement for only the NCS group. After the inclusion of academic self-concept, the model showed that CS parental expectations also mediate the link between self-concept and academic achievement. However, the model showed that the parental expectations of NCS play a lesser role in mediating the link between academic self-concept and their children’s academic achievement. Despite the differences, the results provide evidence for the generalizability of the cognitive-affect model.