An antenna structure includes a first radiation element, a second radiation element, a third radiation element, a fourth radiation element, a fifth radiation element, and a dielectric substrate. The first radiation element has a feeding point. The second radiation element is coupled to the first radiation element. The third radiation element is coupled to a first grounding point. The third radiation element is further coupled through the fourth radiation element to a second grounding point. The fifth radiation element is coupled to the third radiation element and the fourth radiation element. The fifth radiation element is adjacent to the second radiation element. The first radiation element and the second radiation element are at least partially surrounded by the third radiation element, the fourth radiation element, and the fifth radiation element.