Abstract: Two thirds of military personnel diagnosed with posttraumatic stress disorder (PTSD) do not engage in treatment. We examined the degree that prejudicial beliefs about people with PTSD negatively affected psychiatric medication acceptance. Public stigma is best defined as negative stereotypes regarding individuals being judged as inferior or weak for having PTSD. In comparison, self-stigma includes internalized negative prejudices about illness control and stability. An important preliminary stage in developing self-stigma is first developing prejudicial beliefs about those with an illness. Active duty soldiers on a U.S. Army post completed surveys of prejudicial beliefs, public stigma, negative beliefs about psychiatric medications, and PTSD symptoms. Soldiers’ Post Deployment Health Reassessment and medical records were accessed to determine the relation between their survey answers and responses to a later offer of psychiatric medication. Importantly, increased prejudicial beliefs (but not public stigma) that oneself is to blame for having PTSD were associated with a reduced likelihood of accepting psychiatric medication. Increased age was also associated with increased likelihood of accepting medication. Antistigma efforts to date may have limited effectiveness by targeting public-stigma rather than self-stigma prejudicial beliefs about personal responsibility in the development of PTSD. The relevance of this finding is vital to developing public health campaigns that maximize treatment acceptance.