Background and objectives: Posttraumatic stress disorder (PTSD) related to childhood abuse (CA) is associated with high symptom complexity. This study examined the efficacy of Imagery Rescripting (ImRs) as a stand-alone treatment versus a sequenced approach with Skills training in Affective and Interpersonal Regulation (STAIR) followed by ImRs for CA-related PTSD. Methods: Outpatients of two mental health clinics with CA-related PTSD (N = 61) were randomly assigned to ImRs (16 sessions; n = 21), STAIR/ImRs (8 STAIR-sessions followed by 16 ImRs-sessions; n = 20), or Waitlist (8 weeks; n = 20). Patients of the waitlist condition were also randomized to the two active conditions for comparison of STAIR/ImRs (total n for this condition = 31) and ImRs (total n for this condition = 30) and started treatment after waitlist completion. Assessments took place at pre-treatment, after each treatment phase and at 12-week post-intervention follow-up. PTSD symptoms and diagnosis were primary outcome measures, and depression, emotion regulation and interpersonal functioning were secondary outcomes. Results: ImRs showed greater reduction of PTSD severity (effect sizes ES 1.40–1.63) than STAIR (ES, 0.23–0.33) as compared to waitlist. When comparing STAIR/ImRs and ImRs directly, (i.e. including re-randomized Waitlist-patients), PTSD symptoms reduced significantly (within condition ES, 1.64–2.10) and improved further to 12-week follow-up (within-condition ES, 2.33–2.66), with no significant difference between both conditions (between-condition ES, 0.21–0.45). Loss of PTSD diagnosis was achieved by 70% in the ImRs condition and 86% in the STAIR/ImRs condition. Limitations: The sample size was relatively small. Conclusions: Results show that ImRs is an effective treatment for CA-related PTSD, whereby the current data do not convincingly show an additive effect of STAIR.