The current study’s goal was to provide a comprehensive review of current subthreshold posttraumatic stress disorder (PTSD) rates among U.S. military veterans and service members. PubMed, PsycInfo, ProQuest, Web of Knowledge, Google Scholar, and any relevant articles’ reference lists identified studies of subthreshold PTSD in the U.S. military. Search terms included PTSD in combination with partial, subthreshold or sub-threshold, subsyndromal or sub-syndromal, subclinical or sub-clinical, and military or veteran. Sixteen articles met criteria for review. Current subthreshold PTSD rates ranged from 2.3% to 22.3%, with a weighted mean rate of 7.6%. Definitional variation within and across the “below threshold” terms produced some variability in rates reported. Few studies consistently reported on impairment and comorbidity in the subthreshold PTSD population. Variability of current subthreshold PTSD rates may be due to methodological issues such as sampling methods, sample sizes, and how below threshold PTSD was assessed and defined. Based on our findings, we provide a number of recommendations that can be used to inform future research of subthreshold PTSD among U.S. military veterans and service members. These recommendations include having a standardized term and definition, determining how to more properly assess subthreshold PTSD symptomatology, clarifying subthreshold PTSD diagnostic stability, and identifying appropriate sampling methods.