Transitioning out of the military can be a time of change and challenge. Research indicates that altered threat monitoring in military populations may contribute to the development of psychopathology in veterans, and interventions that adjust threat monitoring in personnel leaving the military may be beneficial. Australian Defence Force personnel (N = 59) transitioning from the military were randomized to receive four weekly sessions of either attention-control training or a placebo attention training. The primary outcome was symptoms of posttraumatic stress disorder (PTSD), as measured using the PTSD Checklist for DSM-5 (PCL-5) at posttreatment. Following training, participants who received attention-control training reported significantly lower levels of PTSD symptoms, Hedges’ g = 0.86, 95% CI [0.37, 1.36], p =.004, and significantly improved work and social functioning, Hedges’ g = 0.93, 95% CI [0.46, 1.39], p =.001, relative to those in the placebo condition. Moreover, no participants who received attention-control training worsened with regard to PTSD symptoms, whereas 23.8% of those who received the placebo attention training experienced an increase in PTSD symptoms. The preliminary findings from this pilot study add to a small body of evidence supporting attention-control training as a viable indicated early intervention approach for PTSD that is worthy of further research.