Cell-surface markers for prospective isolation of stem cells from human skeletal muscle have been difficult to identify. Such markers would be powerful tools for studying satellite cell function during homeostasis and in pathogenesis of diseases such as muscular dystrophies. In this study, we show that the tetraspanin KAI/CD82 is an excellent marker for prospectively isolating stem cells from human fetal and adult skeletal muscle. Human CD82+ muscle cells robustly engraft into a mouse model of muscular dystrophy. shRNA knockdown of CD82 in myogenic cells reduces myoblast proliferation, suggesting it is functionally involved in muscle homeostasis. CD82 physically interacts with alpha7beta1 integrin (α7β1-ITG) and with α-sarcoglycan, a member of the Dystrophin-Associated Glycoprotein Complex (DAPC), both of which have been linked to muscular dystrophies. Consistently, CD82 expression is decreased in Duchenne muscular dystrophy patients. Together, these findings suggest that CD82 function may be important for muscle stem cell function in muscular disorders. Display omitted •Tetraspanin CD82 is a marker for prospective isolation of human muscle stem cells•CD82 knockdown in myogenic cells decreases their proliferation•CD82 is in a protein complex with α7-integrin and α-sarcoglycan•CD82 expression is decreased in dystrophic human muscle stem cells In this article, Alexander, Rozkalne, and colleagues describe the identification of CD82 as a prospective marker for human muscle stem cells. Knockdown of CD82 in myogenic cells reduces myoblast proliferation and CD82 expression is reduced in dystrophic muscle stem cells, suggesting a link with muscle disease.