Research Findings: This study employed data from the TIMSS 2015 survey to investigate whether parental educational involvement behaviour in early childhood and parental attitudes towards education can enhance children's mathematics achievement in the 4th grade via influencing children's learning interests. Samples from Singapore (N=6237) and Hong Kong (N=3316), which share similar cultural backgrounds, and students demonstrating outstanding mathematical performance were selected to examine whether a hypothesized model fit the data. The overall model fit was found good. As hypothesized, after controlling for gender, immigration status, and family learning resources variables, both parental involvement in learning activities and parental attitudes towards education had positive significant effects on children's mathematics achievement in the 4th grade. However, a variation was also discovered in terms of the influences of parental attitudes in the two samples. Practice or Policy: The current findings shed light on the importance of parents' attitudes on education and their involvement in their children's mathematics activities during early childhood. The importance of family education should be communicated thoroughly to the public, and the government should provide more support for parents to involve more in early learning activities at home.