In this study, we assessed how attachment orientations and degree of relationship dependence influence individuals' own behavior and their partners' behavior in a stressful situation using the Actor-Partner Interdependence Model (APIM; Kashy & Kenny, 2000). Dating couples were videotaped while the female partner was waiting to engage in an anxiety-provoking task. Raters then evaluated the behavior of each partner on theoretically relevant dimensions. We found that more avoidantly attached individuals behaved more negatively toward their partners. Moreover, people behaved more negatively if their partners were more avoidant. Very few direct effects of dependence emerged. However, attachment orientations, particularly avoidant attachment and level of dependence, interacted to predict the behavior of both partners. In particular, less avoidant and highly dependent people behaved less negatively toward their partners, whereas more avoidant and less dependent people behaved more negatively. These results are discussed in terms of attachment theory, interdependence theory, and the APIM.