An electronic device is provided, which is for coupling to another electronic device in a side-by-side manner, and the electronic device includes a substrate, a first thermal dissipation sheet and a thermal dissipation element. The substrate includes a first surface and a second surface. The first thermal dissipation sheet is disposed on the first surface. The thermal dissipation element is disposed on the substrate. The first thermal dissipation sheet is disposed between the thermal dissipation element and the substrate, and the thermal dissipation element at least partially overlaps the first thermal dissipation sheet.