An optical module and an electronic device are provided. The optical module includes a substrate, a first light guide plate, a first light-emitting element, a reflective layer, a first pattern layer, a first light-shielding structure, and a beam splitting layer. The first light guide plate has first and second surfaces opposite to each other. The second surface faces the substrate. The first light-emitting element has a light output surface facing a side portion of the first light guide plate. The reflective layer is arranged between the substrate and the first light guide plate. The first pattern layer is formed on the first light guide plate. The first light-shielding structure covers a part of the substrate, and the first surface of the first light guide plate. The beam splitting layer is disposed above the first light guide plate and the first light-shielding structure.