Children’s competence levels before or at school onset are good predictors of their attainment over the school years. Nevertheless, there are large differences in the level of numeracy and literacy knowledge among children at school entry and this initial knowledge gap has long-lasting negative consequences for the poor performers. Here we used international secondary data from the PIRLS&TIMSS 2011 as well as TIMSS 2011, including background data collected with the Learning to Read Survey to identify early literacy practices that predict later mathematical attainment. Previous studies conducted using the same dataset have reported that early numeracy and literacy abilities before school onset (as reported by parents) are associated with students’ later mathematical and reading attainment, respectively. Nevertheless recent theoretical frameworks of early mathematical development include certain literacy skills as an independent predictor of mathematical performance. Using ordinary least square regression models we found that early numeracy competences consistently predicted later mathematical attainment while the effects of early literacy competences were variable and not always significant for the individual countries. Results also showed a stronger influence of early reading abilities than of early writing abilities on mathematical attainment. The identified effects were independent of children’s gender, home resources for learning, parents’ highest education and occupation level, student years of pre-school attendance and early numeracy abilities. This report complements and extents previous body of research by determining the relative impact that early literacy skills have on later mathematical attainment across EU countries. Findings highlight the importance of including numeracy and literacy practices in the preprimary curriculum as well as the challenges of implementing ECEC curricula on the basis of identified best practices from international research.