We argue that a relationship development perspective is useful for understanding the experience of jealousy in romantic relationships In particular, we highlight relational uncertainty and intimacy as two indicators of relationship development that are likely to coincide with people's propensity to experience cognitive and emotional jealousy. Because recent theoretical insights about jealousy have stemmed from an attachment perspective, we also examined the extent to which people's attachment orientation predicted their experience of jealousy. We conducted a study in which 132 individuals involved in dating relationships reported on characteristics of themselves and their relationships. Consistent with our predictions, relational uncertainty was strongly tied to cognitive jealousy, and intimacy was closely linked to emotional jealousy. Also as expected, attachment anxiety exerted a direct positive effect on emotional jealousy. Taken together, these results shed light on how the experience of jealousy is associated with both relationship and individual characteristics.