Manual signing is a type of unaided communication strategy that is frequently considered for nonverbal and minimally verbal people with severe disabilities. A considerable amount of research has focused on evaluating procedures for teaching manual signing as an alternative or supplement to speech. This chapter provides an overview of the literature on teaching manual sign-based communication strategies to people with severe disabilities. Indications and contraindications for the use of manual signing are delineated. Factors to consider when implementing manual signing interventions are discussed.