Research on stress and coping has typically been pursued from a structural or a process perspective. However, both approaches are limited in predicting future behavior because they fail to account for meaningful situation-to-situation variation in stress and coping behaviors. The present research applied multi-level modeling to simultaneously examine within-subjects and between-subjects relations to account for stress and coping processes. Specifically, individuals were characterized in terms of a set of coefficients that captured how each of their stress and coping behaviors varied reliably as a function of the features, or psychological meanings, contained in a situation. Results indicated beyond any reasonable doubt that in the populations of individuals and situations examined: (1) that psychological features of situations predicted variation in stress and coping behaviors; (2) there were reliable individual differences in if...then situation-behavior relations reflected by each individual's level-1 coefficients; (3) these if...then situation-behavior relations, or behavioral signatures, were stable over a one-week period; (4) individual difference variables (e.g., narcissism) predicted reliable individual differences in if...then situation-behavior relations; and (5) that at least for some participants, it was possible to predict if...then situation-behavior relations derived from real-life situations (using a daily diary task) on the basis of a laboratory assessment. Through the use of a highly-repeated within-subjects research design (Shoda, 2003) and the data analytic technique of FILM, the present research integrated both structural and process approaches to personality by demonstrating that within-person variation in stress and coping behaviors across situations is meaningful in that it can be accounted for by the psychological features embedded within each situation. By operationalizing stress and coping signatures as sets of level-1 slopes and by demonstrating that these slopes are stable over time, the present research successfully captured the richness of stress and coping processes, while also allowing for stability. Finally, the present research demonstrated that it is possible to predict stress and coping behaviors, but doing so requires information about both the person (which features are psychologically active) and the situation (which features are present).