This collection addresses issues of authenticity in second language contexts from a variety of theoretical and methodological approaches along three principal themes: What is authentic language? Who is an authentic speaker? How is authenticity achieved? The volume responds to these questions by bringing together scholars working in a range of contexts, including with language learners in the classroom and in residence or study abroad, with a variety of second or additional languages: Chinese, English, French, German, Japanese and Spanish. Contributions focus on authenticity as it relates to patterns of language and meaning, and to agency, identity and culture, and serve as an opening to an extended conversation about the nature of authenticity and its development in L2 contexts. This volume is relevant for students and scholars interested in learning about or investigating questions of authenticity and interaction in a wide range of language learning contexts.