Perceived responsiveness is a fundamental ingredient of satisfying romantic relationships, especially insofar as it facilitates the development of intimacy. This study investigates how partner's concrete responsive acts-named here enacted responsiveness-affect the perception of responsiveness in the daily life of dating couples. Additionally, the subsequent association of perceived partner responsiveness with intimacy was examined. Data from both partners in 102 young heterosexual couples were gathered simultaneously 4 times a day over one week. Multilevel analysis within the framework of the actor-partner interdependence mediation model showed that perception of responsiveness is predicted by partner's enacted responsiveness. However, own enacted responsiveness also predicts own perception of responsiveness in the partner, suggesting a projection process. Perception of responsiveness, in turn, predicts not only own but also partner's feelings of intimacy, demonstrating an intimacy enhancing effect of being perceived as a responsive partner. Mediation analysis showed that perception of responsiveness mediates the effects of both own and partner's enacted responsiveness on intimacy. It can be concluded that the development of intimacy in the daily life of romantic couples is truly an interactive process that ought to be investigated from a dyadic perspective.