Despite wide recognition of the importance of interpersonal problems in binge eating disorder (BED), the nature of this association remains unclear. Examining the direction of this longitudinal relationship is necessary to clarify the role that interpersonal problems play in the course of binge eating problems, and thus to specify treatment targets and mechanisms. This study aimed to articulate the bidirectional, longitudinal associations between BED and both the general severity of interpersonal problems as well as warm and dominant interpersonal styles. Severity and styles of interpersonal problems and BED symptoms were measured at baseline, 12 weeks, 24 weeks, and 36 weeks in a sample of 107 women in treatment for BED. Results from bivariate latent change score models indicated that interpersonal problem severity and BED symptoms are associated longitudinally but do not directly influence each other. The results indicated a bidirectional interrelation between binge eating symptoms and dominance such that less dominance predicted greater decreases in binge eating problems, and less binge eating symptoms predicted greater increases in dominance. We also found that binge eating symptoms positively predicted changes in warmth (i.e., less binge eating symptoms predicted less increases or more decreases in warmth). These findings highlight the importance of using dynamic models to examine directionality and delineate the distinct roles of interpersonal severity and styles in BED trajectories.