In light of the recent incorporation of the DSM-5, this updated comprehensive review of racial/ethnic differences in Posttraumatic Stress Disorder (PTSD) makes a significant and timely contribution for clinicians and researchers. Racial/ethnic differences in the prevalence and symptom expression of PTSD are the focus of the current review. In particular, this review examines differences in PTSD expression and prevalence among three major racial/ethnic groups in the United States: African American, Hispanic/Latino, and Asian/Asian Americans. Further, cultural factors believed to influence the epidemiology and phenomenology of PTSD, such as differential rates of trauma exposure, acculturation, racism, and stigma, are discussed within the context of PTSD expression and symptom disclosure. The current review examines empirical literature published since 2000 on academic databases including PsychInfo, PubMed, PsychARTICLES, Psychiatry Online, Psychology and Behavioral Sciences, with aggregate data prioritized when possible. After a general summary of the major findings of the breadth of topics described above, implications for improving treatment utilization, retention and outcomes across diverse racial/ethnic groups based on research findings are discussed. Finally, directions for future empirical examination into this important area are offered.