An antenna structure includes a ground element, a first radiation element, a second radiation element, a third radiation element, and a nonconductive support element. The first radiation element is coupled to a first grounding point on the ground element. The second radiation element has a feeding point. The second radiation element is adjacent to the first radiation element. The third radiation element is coupled to a second grounding point on the ground element. The third radiation element is adjacent to the second radiation element. The first radiation element, the second radiation element, and the third radiation element are disposed on the nonconductive support element. The second radiation element is at least partially surrounded by the first radiation element. The third radiation element is at least partially surrounded by the second radiation element.