This study investigated both the quality of sibling relationships and the psychological adjustment siblings experienced across two groups: siblings of children who are deaf or hard of hearing compared to siblings of children with no disability. Twenty-four siblings of children with hearing loss and 24 siblings of children without a disability participated in the study and were evaluated based on behavioral problems and social competence. We used standardized written questionnaires to measure the psychological adjustment of the siblings. The results showed no significant differences in the quality of the sibling relationship. Parents of children who are deaf or hard of hearing reported fewer internalizing behavior problems (e.g., feelings of anxiety/depression or withdrawn behavior) in the siblings in comparison to parents whose children did not have a disability. There were no significant differences between both groups regarding their social competence. In both groups, positive sibling relationships were related to fewer emotional and behavioral problems and increased social competence, whereas negative sibling relationships had a negative influence on the development of behavioral problems and social competence. Finally, in accordance with the siblings of children without hearing loss, the perception of the siblings' social competence of parents of children who are deaf or hard of hearing broadly matched the perception siblings had of themselves. Overall, siblings of children who are deaf or hard of hearing are not more susceptible to adaptation problems than siblings of children without a disability. Implications for practice and further research are discussed.