Social support is a known protective factor against the negative psychological impact of natural disasters. Most past research has examined how the effects of exposure to traumatic events influences whether someone meets diagnostic criteria for depression and posttraumatic stress disorder (PTSD); it has also suggested sequelae of disaster exposure depends on whether survivors are displaced from their homes. To capture the full range of the psychological impact of natural disasters, we examined the buffering effects of social support on depressive symptoms and cluster‐specific PTSD symptoms, with consideration of displacement status. In a survey conducted 18 to 24 months after Hurricane Katrina, 810 adults exposed to the disaster reported the number of Katrina‐related traumatic events experienced, perceived social support 2 months post‐Katrina, and cluster‐specific PTSD and depressive symptoms experienced since Katrina. Analyses assessed the moderating effects of social support and displacement and the conditional effects of displacement status. Social support significantly buffered the negative effect of Katrina‐related traumatic events on depressive symptoms, B = −0.10, p = .001, and avoidance and arousal PTSD symptoms, B = −0.02, p = .035 and B = −0.02, p = .042, respectively. Three‐way interactions were nonsignificant. Conditional effects indicated social support buffered development of depressive symptoms across all residents; however, the moderating effects of support on avoidance and arousal symptoms only appeared significant for nondisplaced residents. Results highlight the protective effects of disaster‐related social support among nondisplaced individuals, and suggest displaced individuals may require more formal supports for PTSD symptom reduction following a natural disaster.