The chapter focuses on the interactions between the two major linguistic players in Egypt during the Ptolemaic and Roman periods, Egyptian and Greek. Egyptian was the majority language, while in the aftermath of the country’s conquest by Alexander of Macedon, Greek was imposed as administrative language and held sway in elite and urban circles until the Arab conquest. The study reviews the source materials – chiefly bilingual papyri and archives – that reveal the zones of interaction between the two languages. It also attempts to sketch the changing relationship between Egyptian and Greek across time through a series of case studies. Special attention is paid to bilingualism in religion-related settings – temples, temple-run scriptoria, funerary industry – and to bilingual professionals linked to temples, ranging from priests and scribes to embalmers and dream interpreters. I will also show that during the first three centuries of the Roman rule text production in the magico-religious domain became the hub for graphic experimentation that led to the development of the Coptic script, an alphabetic script for Egyptian based on Greek.