The importance of home literacy environment (HLE) for the development of children’s reading achievement is emphasised in numerous studies (for an overview see McElvany, 2008). HLE encompasses the resources and opportunities that support the development of children’s reading in their homes. This comprises family’s literacy practises prior to and during schooling, parents’ involvement in activities that help their children to engage in reading, as well as parents’ beliefs towards reading. As the PIRLS home questionnaires contain variables addressing this subject, the correlation of HLE and reading achievement at grade 4 can be examined internationally. Using data from PIRLS 2006 Stubbe, Buddeberg, Hornberg & McElvany (2007) developed a Rasch score for 29 countries, which allows the quantification of the extent of HLE in the students’ families. This paper addresses research questions, such as how much the PIRLS-countries differ in their average HLE, to what extent reading achievement can be explained by HLE in the different countries, whether there is a correlation between HLE and socio-economic status (SES) and if so, can HLE explain social disparities in reading achievement. Substantial differences between the participating countries were found in the extent of HLE and the correlation with reading achievement. Students from privileged families show significant higher HLE than students from underprivileged families. We conclude that the promotion of HLE - especially in families with no academic background – can help to decrease social disparities in educational systems.