Children’s development of literacy in multiple languages has received increasing attention in Literacy Studies (I. Reyes). Researchers have noted the role that family support plays in children’s biliteracy development (Bauer and Gort; Gregory; Li; M. Reyes). Yet the impact of this support on the adult literacies of parents has received much less attention. This study focuses on Arab immigrant parents’ participation in their children’s emergent biliteracy, on the development of digital and transnational literacies by immigrant parents, and on how specifically they are influenced by the digital technologies used to support their children’s developing biliteracy in Arabic and English. We use the framework of Digital Biliteracy, which focuses on “the process of developing literacy in two language[s] through the use of digital technologies” (Al-Salmi, “Digital Biliteracy as a Social Practice” 4352), to examine digital literacy development in two languages among immigrant families. In this qualitative case study of transnational literacies of Arab immigrant mothers, we show that as these parents become involved in their children’s biliteracy, they use digital technologies to produce and interpret written texts in English and Arabic. In doing so, these mothers’ literacies are shaped through the process of helping their children become literate in Arabic and English via on-line and digital technologies.