A light-guiding mouthguard assembly has a light-transmittable mouthguard and two light-guiding strips. The light-transmittable mouthguard has a teeth-containing channel formed along a curve as a teeth arch. The two light-guiding strips are located on opposite sides of the teeth-containing channel respectively. Each one of the two light-guiding strips is mounted through two opposite terminals of the light-transmittable mouthguard along the teeth-containing channel. An exterior surface of each one of the two light-guiding strips is light-transmittable.
