An antenna structure includes a metal housing, a first feed source, a first ground portion, and a first switching circuit. The metal housing includes a front frame, a backboard, and a side frame. The side frame defines a slot and the front frame defines a first gap and a second gap. The metal housing is divided into at least a first portion by the slot, the first gap, and the second gap. The first feed source is electrically connected to the first portion for supplying current to the first portion. The first ground portion is electrically connected to the first portion for grounding the first portion. One end of the first switching circuit is electrically connected to the first portion. Another end of the first switching circuit is grounded.