An antenna structure including a conductive housing, a substrate, a ground element and a radiation element is provided. The conductive housing includes an open slot and a conductive segment adjacent to each other. The radiation element is disposed on a first surface of the substrate and is electrically connected to the ground element. A second surface of the substrate faces the open slot and the conductive segment. The ground element is electrically connected to the conductive housing. The radiation element has a feeding point and forms a first path. An orthogonal projection of the radiation element on the conductive housing is partially overlapping with the conductive segment such that the conductive housing and the radiation element form a second path. The antenna structure operates in a first band and a second band through the first path and the second path.