Energy absorbing webbing is provided for use in child safety seat and child restraint devices. A harness system includes energy-absorbing regions into the construction of the harness to allow some release or extension of the harness during use. The energy-absorbing regions of the harness are formed using energy-absorbing webbing in a given region or regions to permit the webbing to extend or elongate so that strong forces are not fully and directly imparted to the child. The energy-absorbing region may be installed at various positions within the child safety seat and harness system and may be incorporated into the child safety harness as original equipment or as a retrofit feature.