This study investigated links between interparental conflict appraisals (specifically threat and self‐blame), sibling relationship quality (positive and negative dimensions), and anxiety in sibling pairs comprised of an adolescent and a younger sibling close in age. Sibling relationship quality was measured through behavioral observation. Links between self‐blame and anxiety were moderated by sibling relationship quality. In older siblings, positive behavior with a sibling was associated with an attenuated relation between self‐blame and anxiety. A paradoxical moderating effect was found for negative interactions; for both younger and older siblings, a relation between self‐blame and anxiety was weakened in the presence of sibling negativity. Results offered support for theorized benefits of sibling relationship quality in helping early adolescents adjust to conflict between parents.