While expectations are high for early childhood education to support students' reading literacy, research findings are inconclusive. The purpose of the study is to estimate the effect of preschool non-participation on reading literacy at the end of primary school. That is, what is the average achievement of children who did not attend preschool compared to what it would have been if they had attended preschool? Using PIRLS 2011 data, we employ propensity score matching to approximate a randomized experiment on a large-scale basis to estimate this effect for nine countries. We find that children who did not attend preschool come from disadvantaged backgrounds in all countries. However, with the exception of two countries, our study shows that their reading achievement at the end of primary school is not statistically significantly lower than the performance of matched children from similar backgrounds who attended preschool. Keeping in mind some methodological limitations, we discuss the findings of our study from a policy perspective.