A lamp, a hanging transparent lamp and a lamp system are provided. The lamp includes a frame body, a light guide plate, a light source and a circuit assembly. The frame body includes side covers, side bars, a first integrating member and a second integrating member. Each of the side covers comprises a carrying portion. Each of the two side covers is partitioned into an upper space and a lower space by the side bar. The light guide plate is held on the carrying portions. The light guide plate has a first light-emitting surface and a second light-emitting surface. Only side edge portions of the first light-emitting surface and the second light-emitting surface are covered by the frame body. The light source is disposed adjacent to the side surface of the light guide plate. The circuit assembly is connected to the light source to form an electrical loop.