While diagnosis of PTSD is based on behavioral symptom clusters that are most directly associated with brain function, epigenetic studies of PTSD in humans to date have been limited to peripheral tissues. Animal models of PTSD have been key for understanding the epigenetic alterations in the brain most directly relevant to endophenotypes of PTSD, in particular those pertaining to fear memory and stress response. This chapter provides an overview of neuroepigenetic studies based on animal models of PTSD, with an emphasis on the effect of stress on fear memory. Where relevant, we also describe human-based studies with relevance to neuroepigenetic insights gleaned from animal work and suggest promising directions for future studies of PTSD neuroepigenetics in living humans that combine peripheral epigenetic measures with measures of central nervous system activity, structure and function.