An exemplary key module includes a elastic assembly, a light guide plate, and a key cap. The elastic assembly is including a flat plate and a resilient member. The light guide plate is defining at least one through hole for the resilient member to extend through. The light guide plate is disposed above and in parallel to the flat plate. The key cap is resiliently supported by the resilient member. The light guide plate transmits light through at least a portion of the key cap.