A longitudinal study evaluated associations between intimacy and relational uncertainty and characteristics of interdependence within nonmarital romantic relationships. Three hundred and fifteen college students in the United States completed a Web-based survey about their relationship weekly for 6 weeks. Results indicated nonlinear associations between intimacy and relational uncertainty and perceptions of a partner’s interference (p < .001) that were inconsistent with hypotheses. Intimacy was positively associated with a partner’s influence in and facilitation of activities (p < .001). An interaction between intimacy and a partner’s influence predicted a partner’s interference, such that a partner’s influence was more positively associated with interference at low, compared to high, intimacy (p < .05). The implications of these findings for rethinking the relational turbulence model are discussed.