Conservation of resources (COR) theory has proven a useful framework for understanding posttrauma adjustment. A key tenet of this theory is the centrality of resource loss in determining adjustment. However, COR theory research has often been limited by retrospective research design, a focus on material loss (e.g., one's home), and a lack of attention to other adjustment predictors. This study examined whether psychosocial resource loss prospectively predicted PTSD symptomatology both immediately and 8 months following a campus shooting in a sample of college women (n = 691). Results supported that resource loss predicted symptomatology, even after controlling for other predictors, including prior trauma, psychological distress, initial PTSD symptomatology, and shooting exposure. Implications of the results for research and intervention following mass trauma are discussed.