In this study we sought to determine whether sibling temperaments moderated the associations of parent-child relationship quality and family problem-solving behavior with sibling relationship quality. Observational assessments of mother-child and father-child relationship quality, family problem-solving behavior, and sibling relationship quality were obtained from the families of 49 pairs of brothers and 46 pairs of sisters. Mean ages were 10-2 for older siblings and 7-6 for younger siblings. Parent-reported child temperament assessments were also obtained. The links among mother-older child relationship quality, father-older child relationship quality, and sibling relationship quality were moderated by the older sibling's temperament. The younger and older siblings' temperaments moderated the associations between the quality of the father-younger sibling and sibling relationships. The association between family problem-solving behavior and sibling relationship quality was not moderated by sibling temperaments.