This pediatric case report describes a 3-year-old with duodenal obstruction due to a retroperitoneal hematoma following seatbelt injury, successfully managed with conservative treatment despite initial surgical intervention for gastric perforation. Careful monitoring using clinical status, nasogastric output, and selective imaging allowed resolution of the obstruction without additional surgery, highlighting that nonoperative management can be effective in hemodynamically stable patients without ongoing bleeding or ischemic complications.