Based on a sample of 60 children, 30 with juvenile diabetes, the self‐concepts of well siblings were evaluated as a function of (a) birth order, (b) sex of the children, and (c) sex of the sibling pairs. Siblings of diabetic children reported lower overall self‐concept scores. Younger siblings also had lower scores although this finding was common to both healthy and diabetic sibling pairs. Sibship to a male was associated with lower self‐concept scores, and having a diabetic brother and being male led to the lowest self‐concept scores. Implications are discussed in terms of research and suggestions for prevention and intervention are offered.