Home shared book reading during the preschool years is a strong predictor of students' reading achievement in primary school, and, according to Sénéchal (2012), it can benefit more children from low socioeconomic status (SES) backgrounds. This study examines the association between frequency of book reading before the start of compulsory education and the reading achievement of 4th-grade students whose parents have high and low education levels in 22 European countries. Using data from the Progress in International Reading Literacy Study (PIRLS 2011), we show that the contribution of shared reading for the achievement of students from distinct SES backgrounds is different in different countries and that shared reading does not always benefit more children from low-SES backgrounds. Results are discussed in light of Sénéchal's home literacy model, the dynamics of cultural capital, and current policy efforts to support children's literacy development in European countries.