© 2020 Elsevier Inc. All rights reserved. An increasing body of research has focused on elucidating the genetic etiology of posttraumatic stress disorder (PTSD). This chapter first reviews the developments and existing knowledge in the rapidly growing field of PTSD genomics. Next, we describe the PTSD working group of the Psychiatric Genomics Consortium (PGC-PTSD), which was created to identify the genetic architecture underlying susceptibility to PTSD. We discuss recent developments underway by the PGC-PTSD working group, as well as address some of the unique considerations when investigating the genomics of PTSD. Five separate working groups within the PGC-PTSD are described with respect to their contributions to the overarching goal of answering innovative questions regarding the genetic and biological framework of PTSD. Finally, future directions of the overall PGC-PTSD working group, and the field of PTSD genomics as a whole, are discussed.