In a series of five studies a method of assessing relationship thinking and its role in close relationship dynamics was developed. These studies were carried out with college students who responded to questionnaires. Studies 1 and 2 focused on identifying items representing the content and frequency of relationship thinking about participants' present dating relationships. Studies 3 and 4 examined personal characteristics, general relationship schema, and subjective conditions that were related to relationship thinking. Study 5 identified the ability of relationship thinking to predict individuals' perceptions of an interaction with their partners. Results uncovered three types of relationship thinking: partner, positive affect, and network. Relationship thinking was related in expected ways to several personal characteristics, subjective conditions, and general relationship schema. Relationship thinking was predictive of perceptions of distress-maintaining and relationship-enhancing interactions with the dating partners. The findings suggest increased attention to the social cognitive aspects of close relationships.