The Tongue Drive System (TDS) is a new minimally invasive, unobtrusive, wireless, and wearable tongue-operated assistive technology (AT) that enables individuals with severe physical disabilities to control environments with their free tongue motion. An array of magnetic sensors wirelessly tracks the position of a magnetic tracer attached to the tongue via adhesives or piercing, and a sensor signal-processing (SSP) algorithm converts a set of tongue gestures to user-defined commands in real time . In the external TDS (eTDS), which is undergoing clinical trials, electronics are embedded in a customized headset, which supports the sensors on a pair of bilateral extensions near the cheeks . Considering the importance of such ATs in users' daily lives, the mechanical stability of the eTDS on the head is a concern. In this paper we report an intraoral TDS (iTDS) that reliably fits inside a user's mouth in the form of a dental retainer to be well protected within the oral cavity.