In this paper, we examine the factors that are associated with the probability for a student to be retained in primary school; understanding such phenomenon is very important, because the literature points at claiming that retention perpetrates socioeconomic and educational inequality, instead of reducing it. Empirically, we estimate a multivariate logistic regression with the aim of identifying cross-country determinants of grade retention using data about 16 European countries participating in PIRLS 2011 using data about entry age at school and grade enrollment to identify retained students. Our results highlight that socioeconomic background is not the only factor that plays a role. Early-acquired skills do reduce the probability for a child to become a repeater; thus, the policy-makers should devote their effort in helping families to undertake preschool activities that develop skills also before starting formal schooling. Later assistance with homework is helpful as well, but with a lower magnitude and effect, which is offset if early skills are properly accounted for.