An antenna structure includes a feeding radiation element, a first radiation element, a second radiation element, a third radiation element, a fourth radiation element, a fifth radiation element, and a switch circuit. The feeding radiation element has a feeding point. The second radiation element is coupled through the first radiation element to the feeding radiation element. The third radiation element is coupled to the second radiation element. The fourth radiation element is coupled to the second radiation element. The fourth radiation element and the third radiation element extend in different directions. The fifth radiation element has a tuning point, and is coupled to the feeding radiation element. The feeding radiation element is disposed between the first radiation element and the fifth radiation element. The switch circuit selectively couples the tuning point to a ground voltage.