This chapter provides an overview of principles, practices, and procedures associated with the exposure-based treatment of childhood selective mutism (SM), a relatively rare but highly impairing anxiety disorder characterized by persistent failure to speak in certain social settings. Recent research has clarified that anxiety and associated avoidance is at the center of SM. In light of growing consensus regarding the critical role of exposure therapy in the treatment of childhood SM, this chapter offers a guiding overview of the key elements of exposure-based treatment for SM—including proper assessment, psychoeducation, reinforcement, stimulus fading, shaping, coping strategies, development of a fear hierarchy, graduated exposures, reinforcement, and homework. We consider important developmental factors throughout, and discuss issues related to promoting generalization of skills in the community, collaborating with schools, calibrating for comorbidity, and improving treatment access. We conclude with a discussion of future directions in the exposure-based treatment of childhood SM.