Objective: This study examines the association between parental relationship churning (i.e., the separation and reunification of one's biological parents) and adolescent well-being. Background: Research examines how instability in parental romantic relationships is linked to adolescent well-being, but it has largely neglected instability and transitions that occur within, rather than between, relationships. Family stress and family boundary ambiguity theories suggest that adolescents from churning families will experience deleterious outcomes when compared with their counterparts in stably together families. Method: In this article, the authors used data from the Fragile Families and Child Wellbeing Study (N = 3,327) to examine the association between parental relationship churning and adolescent socioemotional and behavioral outcomes (including internalizing behaviors, externalizing behaviors, depressive symptoms, anxiety, delinquency, and exclusionary school discipline experience). Results: Adolescents who experience parental relationship churning between birth and age 9 had similar outcomes to their counterparts with