The goals of this study were to examine longitudinal changes in perceived control in adolescents' sibling relationships and to describe the nature and correlates of three distinct control patterns: firstborn dominant, equal, and secondborn dominant. Firstborn and secondborn adolescents in 184 predominately European-American families participated in home interviews and a series of phone interviews as part of a longitudinal a study of family relationships and adolescent development. Findings revealed changes in control over 3 years as well as sibling differences. In addition, different patterns of control were linked to qualities of the sibling relationship and to adolescent adjustment. The different roles that firstborn and secondborn siblings assume and why these roles are linked to relationship experiences and adjustment are discussed.