An electronic device includes a first housing with a first air inlet and outlet, a heat dissipation assembly, and a filter structure between the first housing and the heat dissipation assembly. The heat dissipation assembly defines a second air inlet and outlet. The first air inlet, the second air inlet, the second air outlet and the first air outlet communicate with each other. The heat dissipation assembly draws air across itself from the two air inlets, and expels the air from the two air outlets. The filter structure covers the second air inlet and defines a plurality of very small holes which function to filter dust out from the incoming air.