The present study addresses the issue of how different forms of cultural capital may influence children's mathematics achievement in economies with different socioeconomic gradients. Data from 73,178 parent-child dyads from 10 economies with different socioeconomic gradients who participated in the Programme for International Student Assessment (PISA) 2012 were analysed using hierarchical linear modelling. The cultural capital variables examined comprised the availability of home educational resources and parental educational expectations of their children. Results showed that after controlling for parent education, student gender and student history of repeating grades in the past, there were statistically significant main and interaction effects (home educational resources × parent education and parental educational expectations × parent education) of cultural capital on student achievement. Furthermore, these effects explained more student achievement variance in high than in medium socioeconomic gradient economies (7.45% vs. 2.82% respectively). In particular, the main effects for parental educational expectations, and interaction effect between parental educational expectations and parent education were more pronounced in high as compared with medium socioeconomic gradient economies. Overall, the results underscore the challenges confronting low socioeconomic status (SES) parents who aspire for social mobility for their children and the need for high SES parents to strategically "activate" their cultural capital advantages to benefit their children's achievement maximally.