An antenna structure includes a ground element, a first radiation element, a second radiation element, a dielectric substrate, a first feeding element, a second feeding element, a third feeding element, and a fourth radiation element. The dielectric substrate has a first surface and a second surface. The first radiation element is disposed on the first surface. The second radiation element is adjacent to the first radiation element, and is separate from the first radiation element. The first feeding element has a first feeding port, and is coupled to the first radiation element. The second feeding element has a second feeding port, and is coupled to the first radiation element. The third feeding element has a third feeding port, and is coupled to the first radiation element. The fourth feeding element has a fourth feeding port, and is coupled to the first radiation element.