Posttraumatic stress disorder (PTSD) is a debilitating psychiatric disorder with a lifetime prevalence of nearly 8% in the general population. While the underlying molecular and cellular mechanisms of PTSD remain unknown, recent studies indicate that PTSD is associated with aberrant gene expression in brain as well as peripheral blood cells. The advent of next-generation sequencing technologies will allow us to elucidate the gene expression changes occurring in both brain and blood of patients with PTSD. RNA sequencing allows for analysis of the amount of transcript being made as well as alternative splicing, novel transcript identification, microRNA, and noncoding RNA quantification. Here we provide an overview of the different types of transcriptomic technologies as well as the gene expression studies performed in human peripheral blood and animal models of PTSD, and review the human PTSD postmortem brain gene profiling studies performed to date.