An electrical stimulation system includes an electrical stimulation lead with at least one lead body, electrodes disposed along the distal end portion of the lead body(ies), terminals disposed along the proximal end portion of the lead body(ies), and conductors electrically coupling the terminals to the electrodes. The electrical stimulation system also includes a lead extension coupleable to the electrical stimulation lead. The lead extension includes a connector for receiving the proximal end portion of the electrical stimulation lead. The electrical stimulation system further includes a sheath defining a sheath lumen to slidingly receive a portion of the electrical stimulation lead or a portion of the lead extension or a portion of both the electrical stimulation lead and the lead extension. The sheath includes a flexible sheath body and an elongate RF shield disposed within the sheath body and extending along the sheath.