In the current study, we took a unique dyadic approach to examine how people’s relationship quality following an earthquake was associated with their and their partner’s posttraumatic stress symptoms (PTSS) and whether support exchanges in the relationship protected relationship quality in the face of this adversity. Ninety-nine heterosexual couples were studied over 4 time points for approximately 15 months following the Canterbury, New Zealand, earthquakes. The data were analyzed using moderated growth-curve modeling in an Actor–Partner Interdependence Model framework. In line with predictions, both partners’ PTSS scores were associated with lower relationship quality at Time 1 (the first assessment postearthquake). These associations, however, were attenuated by more frequent provisions of support between relationship partners, especially for men, at least in the short term. The associations, however, changed across time, suggesting that coping in a relationship context post trauma is a dynamic, fluid process. These findings demonstrate the importance of adopting a dyadic perspective and examining effects across time. They also highlight the importance of examining resources within the relationship context to more fully understand how PTSS affects relationships.