This paper introduces our special issue about ideologies in sign language vitality and revitalization and discusses ideologies related to the vitality of sign languages. Rather than taking for granted the notions of vitality and endangerment or developing criteria for measuring sign language vitality, the papers in this issue will provide a discursive construction of sign language endangerment. This construction in turn provides critical and historical reflection on how vitality has emerged as a concern for sign languages in specific local, national, and international contexts, the actors and institutions bringing forward this framing, and in whose interest it is to promote such discourses. The issue will survey how and by whom these ideologies are described, mobilized and legitimized, and what conceptualizations of language are emphasized and by whom.