Abstract: A restraint harness for securing a passenger in a seat of a vehicle includes a plurality of lateral straps, a pair of shoulder straps, a pair of crotch straps, and a plurality of D-ring connectors. The plurality of lateral straps may be configured to encircle a torso of the passenger. At least two lateral straps include a flexible portion allowing the restraint harness to accommodate a variety of torso diameters. The pair of shoulder straps generally extend over left and right shoulders of the passenger from an anterior side of the restraint harness to a posterior side of the restraint harness. The pair of crotch straps generally extend from an anterior side of the restraint harness to a posterior side of the restraint harness. The plurality of D-ring connectors is generally disposed on the posterior side of the restraint harness and configured to provide four points of attachment between the posterior side of the restraint harness and the seat of the vehicle.