This special issue draws attention to literacy and basic literacy education for adult and adolescent migrants with limited or no previous school background, who are learning a second language. This introduction addresses issues closely related to literacy education for this group of migrants, namely human mobility and immobility, including both horizontal (geographical and spatial) and vertical (social) mobility, as well as the interrelation between the two. Whereas some people’s mobility is considered a threat that must be regulated and restricted, other people’s mobility is encouraged. While mobility and diversity have always been intrinsic aspects of human societies, it can be concluded that social, economic and technological changes have intensified migration, the movement of artifacts and communication between people over vast distances. As mobility and diversity have increased, theoretical perspectives and research in applied linguistics and education have emerged. In this special issue, we bring together seven studies of second language and literacy education for adolescent and adult second language learners in different contexts, illustrating both similarities and differences between educational domains. The studies were conducted in Canada, Norway and Sweden. We are happy to say that the authors’ efforts have resulted in a body of work that contributes to research on literacies and literacy education for adults and adolescents with limited previous education. It is also our hope that the articles will inspire additional research in the area in the coming years.