Until recently, the interaction between language and religion as topics relevant to bilingualism or multilingualism has been relatively little explored, although there is an extensive body of research on religious language. This chapter first provides an overview of earlier work, much of it on the translation of sacred texts into various languages. Past research has also identified the linguistic consequences of the spread of various religions, particularly with respect to choice of ritual language and orthographic systems. The language use patterns and practices historically characteristic of different religious traditions, including Buddhism, Christianity, Hinduism, Islam, Judaism, and Quakerism, are reviewed. The chapter then describes the linguistic effects of missionary activity in several postcolonial settings, concentrating mainly on those pertaining to Christian groups. Other recent research has examined the linguistic consequences of linkages between regionally prominent languages and dialects and religious practice in diverse international locations. Relationships between immigration and language maintenance and shift in religious domains are also discussed. The chapter concludes by noting that recent political events, interest in conversion efforts of religions other than Christianity, and growing recognition of the academic legitimacy of the field of language and religion predict a likely increase in applied linguistic research in this area.