An electronic device has a front side and a rear side opposite to each other and includes a back cover and an antenna structure. The back cover is disposed at the rear side. The antenna structure includes a first radiation portion, a second radiation portion and a ground portion. The first radiation portion is disposed at the front side. The second radiation portion is disposed between the first radiation portion and the back cover and is connected to the first radiation portion. The ground portion is disposed between the first radiation portion and the back cover, wherein the second radiation portion is grounded to the back cover through the ground portion.