The work group editing trauma disorders for the upcoming edition of the International Classification of Diseases (ICD-11) made several changes. Specifically, they significantly simplified the guidelines for post-traumatic stress disorder (PTSD) and added a new trauma disorder called complex PTSD (CPTSD). The new domains for PTSD and the addition of CPTSD require new instruments to assess these novel constructs. We developed a measure of PTSD and CPTSD (Complex Trauma Inventory; CTI) according to the proposed ICD-11 domains, creating several items to assess each domain. We examined the factor structure of the CTI (using both exploratory and confirmatory factor analyses) in two separate samples of diverse college students (n1 = 501; n2 = 500), reducing the original 53 trauma items in the item pool to 21 items. Confirmatory factor analyses supported two highly-correlated second-order factors (PTSD and complex factors), with PTSD (i.e., re-experiencing, avoidance, hyper-arousal) and complex factors (i.e., affect dysregulation, alterations in self-perception and alterations in relationships with others) each loading on three of the six ICD-11-consistent first-order factors (RMSEA = .08, CFI = .92, GFI = .87, SRMR = .06). Internal consistency for PTSD (α = .92) and complex factors (α = .93) are excellent.