Social functioning is negatively impacted by the presence of PTSD, while increasing risk of suicidal behavior among individuals with PTSD. However, little research has examined the specific role of social functioning in the association between PTSD and suicidal behavior. Parallel multiple indirect effects analyses were performed to understand the unique indirect effects of four aspects of social functioning. Indirect effects of PTSD on suicidal ideation were significant through three pathways: interpersonal conflict, perceived family support, and interpersonal apprehension. Perceived family support was the only indirect pathway significantly associated with suicide attempt. Findings suggest that social functioning should be assessed and potentially targeted during treatment to help modify the risk for suicidal behavior among individuals with PTSD.