Despite significant stressors facing military families over the past 15 years of wars in Iraq and Afghanistan, no parenting programs adapted or developed for military families with school-aged children have been rigorously tested. We present outcome data from the first randomized controlled trial of a behavioral parent training program for families with a parent deployed to Iraq or Afghanistan. In the present study, 336 primarily National Guard and Reserve families with 4-12-year-old children were recruited from a Midwestern state. At least one parent in each family had deployed to the recent conflicts: Operations Iraqi or Enduring Freedom, or New Dawn (OIF/OEF/OND). Families were randomized to a group-based parenting program (After Deployment, Adaptive Parenting Tools (ADAPT)) or web and print resources-as-usual. Using a social interaction learning framework, we hypothesized an indirect effects model: that the intervention would improve parenting, which, in turn, would be associated with improvements in child outcomes. Applying intent-to-treat analyses, we examined the program's effect on observed parenting, and children's adjustment at 12-months post baseline. Controlling for demographic (marital status, length, child gender), deployment variables (number of deployments), and baseline values, families randomized to the ADAPT intervention showed significantly improved observed parenting compared to those in the comparison group. Observed parenting, in turn, was associated with significant improvements in child adjustment. These findings present the first evidence for the effectiveness of a parenting program for deployed military families with school-aged children.