Abstract: A head-mounted electronic device including a body, a circuit board, and a fan is provided. The body includes a first cover, a second cover, and an annular side wall. The annular side wall is encircled to form two opposite openings, and the first cover and the second cover are assembled on the openings. The first cover has a main air outlet and a pair of first air inlets. The second cover has a pair of second air inlets. The circuit board is disposed in the body and is located between the first cover and the second cover. The fan is disposed on the circuit board and is located in the body. An air intake of the fan faces the first cover. The fan draws air from the pair of first air inlets and the pair of second air inlets, and blows the air out of the main air outlet.