The goal of this research was to explore the development of the interpersonal system mapped by the interpersonal circumplex in early adulthood (ages 18–22). This study uses the Longitudinal Study of Personality Disorders sample (N = 250; 53% female). Participants completed the Revised Interpersonal Adjective Scales (Wiggins, Trapnell, & Phillips, 1988) in their freshman, sophomore, and senior years of college. Estimates of structural, rank-order, mean, individual, and ipsative stability were calculated for the broad interpersonal dimensions of Dominance and Affiliation and also the lower order octant scales. Additionally, the interpersonal profile parameters of differentiation and prototypicality were calculated at each wave and explored longitudinally and also used as predictors of interpersonal stability. We found excellent structural and high rank-order and ipsative stability in the interpersonal scales over this time period. Mean increases on the Affiliation axis, but not on the Dominace axis, were found to mask differential rates of change among the octant scales, along with significant individual variation in the rates of change. Interpersonal differentiation and prototypicality were related to higher stability in overall interpersonal style. Results point to evidence of both stability and nuanced change, illuminating some of the features of the structural variables that can be derived from interpersonal circumplex profiles.